slice - Rust
Description: A dynamically-sized view into a contiguous sequence, `[T]`.

# Primitive Type slice

1.0.0
Expand description

A dynamically-sized view into a contiguous sequence, `[T]`.

Contiguous here means that elements are laid out so that every element is the same distance from its neighbors.

See also the `std::slice` module.

Slices are a view into a block of memory represented as a pointer and a length.

    // slicing a Vec
    let vec = vec![1, 2, 3];
    let int_slice = &vec[..];
    // coercing an array to a slice
    let str_slice: &[&str] = &["one", "two", "three"];

Slices are either mutable or shared. The shared slice type is `&[T]`, while the mutable slice type is `&mut [T]`, where `T` represents the element type. For example, you can mutate the block of memory that a mutable slice points to:

    let mut x = [1, 2, 3];
    let x = &mut x[..]; // Take a full slice of `x`.
    x[1] = 7;
    assert_eq!(x, &[1, 7, 3]);

It is possible to slice empty subranges of slices by using empty ranges (including `slice.len()..slice.len()`):

    let x = [1, 2, 3];
    let empty = &x[0..0];   // subslice before the first element
    assert_eq!(empty, &[]);
    let empty = &x[..0];    // same as &x[0..0]
    assert_eq!(empty, &[]);
    let empty = &x[1..1];   // empty subslice in the middle
    assert_eq!(empty, &[]);
    let empty = &x[3..3];   // subslice after the last element
    assert_eq!(empty, &[]);
    let empty = &x[3..];    // same as &x[3..3]
    assert_eq!(empty, &[]);

It is not allowed to use subranges that start with lower bound bigger than `slice.len()`:

ⓘ

    let x = vec![1, 2, 3];
    let _ = &x[4..4];

As slices store the length of the sequence they refer to, they have twice the size of pointers to `Sized` types. Also see the reference on dynamically sized types.

    let pointer_size = size_of::<&u8>();
    assert_eq!(2 * pointer_size, size_of::<&[u8]>());
    assert_eq!(2 * pointer_size, size_of::<*const [u8]>());
    assert_eq!(2 * pointer_size, size_of::<Box<[u8]>>());
    assert_eq!(2 * pointer_size, size_of::<Rc<[u8]>>());

### §Trait Implementations

Some traits are implemented for slices if the element type implements that trait. This includes `Eq`, `Hash` and `Ord`.

### §Iteration

The slices implement `IntoIterator`. The iterator yields references to the slice elements.

    let numbers: &[i32] = &[0, 1, 2];
    for n in numbers {
        println!("{n} is a number!");
    }

The mutable slice yields mutable references to the elements:

    let mut scores: &mut [i32] = &mut [7, 8, 9];
    for score in scores {
        *score += 1;
    }

This iterator yields mutable references to the slice’s elements, so while the element type of the slice is `i32`, the element type of the iterator is `&mut i32`.

- `.iter` and `.iter_mut` are the explicit methods to return the default iterators.
- Further methods that return iterators are `.split`, `.splitn`, `.chunks`, `.windows` and more.

## Implementations§

Source§

### impl<T> [MaybeUninit<T>]

Source

#### pub const fn write_copy_of_slice(&mut self, src: &[T]) -> &mut [T]
where T: Copy,

🔬This is a nightly-only experimental API. (`maybe_uninit_write_slice` #79995)

Copies the elements from `src` to `self`, returning a mutable reference to the now initialized contents of `self`.

If `T` does not implement `Copy`, use `write_clone_of_slice` instead.

This is similar to `slice::copy_from_slice`.

##### §Panics

This function will panic if the two slices have different lengths.

##### §Examples

    #![feature(maybe_uninit_write_slice)]
    use std::mem::MaybeUninit;

    let mut dst = [MaybeUninit::uninit(); 32];
    let src = [0; 32];

    let init = dst.write_copy_of_slice(&src);

    assert_eq!(init, src);

    #![feature(maybe_uninit_write_slice)]

    let mut vec = Vec::with_capacity(32);
    let src = [0; 16];

    vec.spare_capacity_mut()[..src.len()].write_copy_of_slice(&src);

    // SAFETY: we have just copied all the elements of len into the spare capacity
    // the first src.len() elements of the vec are valid now.
    unsafe {
        vec.set_len(src.len());
    }

    assert_eq!(vec, src);

Source

#### pub fn write_clone_of_slice(&mut self, src: &[T]) -> &mut [T]
where T: Clone,

🔬This is a nightly-only experimental API. (`maybe_uninit_write_slice` #79995)

Clones the elements from `src` to `self`, returning a mutable reference to the now initialized contents of `self`. Any already initialized elements will not be dropped.

If `T` implements `Copy`, use `write_copy_of_slice` instead.

This is similar to `slice::clone_from_slice` but does not drop existing elements.

##### §Panics

This function will panic if the two slices have different lengths, or if the implementation of `Clone` panics.

If there is a panic, the already cloned elements will be dropped.

##### §Examples

    #![feature(maybe_uninit_write_slice)]
    use std::mem::MaybeUninit;

    let mut dst = [const { MaybeUninit::uninit() }; 5];
    let src = ["wibbly", "wobbly", "timey", "wimey", "stuff"].map(|s| s.to_string());

    let init = dst.write_clone_of_slice(&src);

    assert_eq!(init, src);

    #![feature(maybe_uninit_write_slice)]

    let mut vec = Vec::with_capacity(32);
    let src = ["rust", "is", "a", "pretty", "cool", "language"].map(|s| s.to_string());

    vec.spare_capacity_mut()[..src.len()].write_clone_of_slice(&src);

    // SAFETY: we have just cloned all the elements of len into the spare capacity
    // the first src.len() elements of the vec are valid now.
    unsafe {
        vec.set_len(src.len());
    }

    assert_eq!(vec, src);

Source

#### pub fn write_filled(&mut self, value: T) -> &mut [T]
where T: Clone,

🔬This is a nightly-only experimental API. (`maybe_uninit_fill` #117428)

Fills a slice with elements by cloning `value`, returning a mutable reference to the now initialized contents of the slice. Any previously initialized elements will not be dropped.

This is similar to `slice::fill`.

##### §Panics

This function will panic if any call to `Clone` panics.

If such a panic occurs, any elements previously initialized during this operation will be dropped.

##### §Examples

    #![feature(maybe_uninit_fill)]
    use std::mem::MaybeUninit;

    let mut buf = [const { MaybeUninit::uninit() }; 10];
    let initialized = buf.write_filled(1);
    assert_eq!(initialized, &mut [1; 10]);

Source

#### pub fn write_with<F>(&mut self, f: F) -> &mut [T]
where F: FnMut(usize) -> T,

🔬This is a nightly-only experimental API. (`maybe_uninit_fill` #117428)

Fills a slice with elements returned by calling a closure for each index.

This method uses a closure to create new values. If you’d rather `Clone` a given value, use `MaybeUninit::fill`. If you want to use the `Default` trait to generate values, you can pass `|_| Default::default()` as the argument.

##### §Panics

This function will panic if any call to the provided closure panics.

If such a panic occurs, any elements previously initialized during this operation will be dropped.

##### §Examples

    #![feature(maybe_uninit_fill)]
    use std::mem::MaybeUninit;

    let mut buf = [const { MaybeUninit::<usize>::uninit() }; 5];
    let initialized = buf.write_with(|idx| idx + 1);
    assert_eq!(initialized, &mut [1, 2, 3, 4, 5]);

Source

#### pub fn write_iter<I>(&mut self, it: I) -> (&mut [T], &mut [MaybeUninit<T>])
where I: IntoIterator<Item = T>,

🔬This is a nightly-only experimental API. (`maybe_uninit_fill` #117428)

Fills a slice with elements yielded by an iterator until either all elements have been initialized or the iterator is empty.

Returns two slices. The first slice contains the initialized portion of the original slice. The second slice is the still-uninitialized remainder of the original slice.

##### §Panics

This function panics if the iterator’s `next` function panics.

If such a panic occurs, any elements previously initialized during this operation will be dropped.

##### §Examples

Completely filling the slice:

    #![feature(maybe_uninit_fill)]
    use std::mem::MaybeUninit;

    let mut buf = [const { MaybeUninit::uninit() }; 5];

    let iter = [1, 2, 3].into_iter().cycle();
    let (initialized, remainder) = buf.write_iter(iter);

    assert_eq!(initialized, &mut [1, 2, 3, 1, 2]);
    assert_eq!(remainder.len(), 0);

Partially filling the slice:

    #![feature(maybe_uninit_fill)]
    use std::mem::MaybeUninit;

    let mut buf = [const { MaybeUninit::uninit() }; 5];
    let iter = [1, 2];
    let (initialized, remainder) = buf.write_iter(iter);

    assert_eq!(initialized, &mut [1, 2]);
    assert_eq!(remainder.len(), 3);

Checking an iterator after filling a slice:

    #![feature(maybe_uninit_fill)]
    use std::mem::MaybeUninit;

    let mut buf = [const { MaybeUninit::uninit() }; 3];
    let mut iter = [1, 2, 3, 4, 5].into_iter();
    let (initialized, remainder) = buf.write_iter(iter.by_ref());

    assert_eq!(initialized, &mut [1, 2, 3]);
    assert_eq!(remainder.len(), 0);
    assert_eq!(iter.as_slice(), &[4, 5]);

Source

#### pub const fn as_bytes(&self) -> &[MaybeUninit<u8>]

🔬This is a nightly-only experimental API. (`maybe_uninit_as_bytes` #93092)

Returns the contents of this `MaybeUninit` as a slice of potentially uninitialized bytes.

Note that even if the contents of a `MaybeUninit` have been initialized, the value may still contain padding bytes which are left uninitialized.

##### §Examples

    #![feature(maybe_uninit_as_bytes, maybe_uninit_write_slice, maybe_uninit_slice)]
    use std::mem::MaybeUninit;

    let uninit = [MaybeUninit::new(0x1234u16), MaybeUninit::new(0x5678u16)];
    let uninit_bytes = uninit.as_bytes();
    let bytes = unsafe { uninit_bytes.assume_init_ref() };
    let val1 = u16::from_ne_bytes(bytes[0..2].try_into().unwrap());
    let val2 = u16::from_ne_bytes(bytes[2..4].try_into().unwrap());
    assert_eq!(&[val1, val2], &[0x1234u16, 0x5678u16]);

Source

#### pub const fn as_bytes_mut(&mut self) -> &mut [MaybeUninit<u8>]

🔬This is a nightly-only experimental API. (`maybe_uninit_as_bytes` #93092)

Returns the contents of this `MaybeUninit` slice as a mutable slice of potentially uninitialized bytes.

Note that even if the contents of a `MaybeUninit` have been initialized, the value may still contain padding bytes which are left uninitialized.

##### §Examples

    #![feature(maybe_uninit_as_bytes, maybe_uninit_write_slice, maybe_uninit_slice)]
    use std::mem::MaybeUninit;

    let mut uninit = [MaybeUninit::<u16>::uninit(), MaybeUninit::<u16>::uninit()];
    let uninit_bytes = MaybeUninit::slice_as_bytes_mut(&mut uninit);
    uninit_bytes.write_copy_of_slice(&[0x12, 0x34, 0x56, 0x78]);
    let vals = unsafe { uninit.assume_init_ref() };
    if cfg!(target_endian = "little") {
        assert_eq!(vals, &[0x3412u16, 0x7856u16]);
    } else {
        assert_eq!(vals, &[0x1234u16, 0x5678u16]);
    }

Source

#### pub unsafe fn assume_init_drop(&mut self)

🔬This is a nightly-only experimental API. (`maybe_uninit_slice` #63569)

Drops the contained values in place.

##### §Safety

It is up to the caller to guarantee that every `MaybeUninit<T>` in the slice really is in an initialized state. Calling this when the content is not yet fully initialized causes undefined behavior.

On top of that, all additional invariants of the type `T` must be satisfied, as the `Drop` implementation of `T` (or its members) may rely on this. For example, setting a `Vec<T>` to an invalid but non-null address makes it initialized (under the current implementation; this does not constitute a stable guarantee), because the only requirement the compiler knows about it is that the data pointer must be non-null. Dropping such a `Vec<T>` however will cause undefined behaviour.

Source

#### pub const unsafe fn assume_init_ref(&self) -> &[T]

🔬This is a nightly-only experimental API. (`maybe_uninit_slice` #63569)

Gets a shared reference to the contained value.

##### §Safety

Calling this when the content is not yet fully initialized causes undefined behavior: it is up to the caller to guarantee that every `MaybeUninit<T>` in the slice really is in an initialized state.

Source

#### pub const unsafe fn assume_init_mut(&mut self) -> &mut [T]

🔬This is a nightly-only experimental API. (`maybe_uninit_slice` #63569)

Gets a mutable (unique) reference to the contained value.

##### §Safety

Calling this when the content is not yet fully initialized causes undefined behavior: it is up to the caller to guarantee that every `MaybeUninit<T>` in the slice really is in an initialized state. For instance, `.assume_init_mut()` cannot be used to initialize a `MaybeUninit` slice.

Source§

### impl [AsciiChar]

Source

#### pub const fn as_str(&self) -> &str

🔬This is a nightly-only experimental API. (`ascii_char` #110998)

Views this slice of ASCII characters as a UTF-8 `str`.

Source

#### pub const fn as_bytes(&self) -> &[u8]

🔬This is a nightly-only experimental API. (`ascii_char` #110998)

Views this slice of ASCII characters as a slice of `u8` bytes.

Source§

### impl [u8]

1.23.0 (const: 1.74.0) · Source

#### pub const fn is_ascii(&self) -> bool

Checks if all bytes in this slice are within the ASCII range.

Source

#### pub const fn as_ascii(&self) -> Option<&[Char]>

🔬This is a nightly-only experimental API. (`ascii_char` #110998)

If this slice `is_ascii`, returns it as a slice of ASCII characters, otherwise returns `None`.

Source

#### pub const unsafe fn as_ascii_unchecked(&self) -> &[Char]

🔬This is a nightly-only experimental API. (`ascii_char` #110998)

Converts this slice of bytes into a slice of ASCII characters, without checking whether they’re valid.

##### §Safety

Every byte in the slice must be in `0..=127`, or else this is UB.

1.23.0 (const: unstable) · Source

#### pub fn eq_ignore_ascii_case(&self, other: &[u8]) -> bool

Checks that two slices are an ASCII case-insensitive match.

Same as `to_ascii_lowercase(a) == to_ascii_lowercase(b)`, but without allocating and copying temporaries.

1.23.0 (const: 1.84.0) · Source

#### pub const fn make_ascii_uppercase(&mut self)

Converts this slice to its ASCII upper case equivalent in-place.

ASCII letters ‘a’ to ‘z’ are mapped to ‘A’ to ‘Z’, but non-ASCII letters are unchanged.

To return a new uppercased value without modifying the existing one, use `to_ascii_uppercase`.

1.23.0 (const: 1.84.0) · Source

#### pub const fn make_ascii_lowercase(&mut self)

Converts this slice to its ASCII lower case equivalent in-place.

ASCII letters ‘A’ to ‘Z’ are mapped to ‘a’ to ‘z’, but non-ASCII letters are unchanged.

To return a new lowercased value without modifying the existing one, use `to_ascii_lowercase`.

1.60.0 · Source

#### pub fn escape_ascii(&self) -> EscapeAscii<'_> ⓘ

Returns an iterator that produces an escaped version of this slice, treating it as an ASCII string.

##### §Examples

    let s = b"0\t\r\n'\"\\\x9d";
    let escaped = s.escape_ascii().to_string();
    assert_eq!(escaped, "0\\t\\r\\n\\'\\\"\\\\\\x9d");

1.80.0 (const: 1.80.0) · Source

#### pub const fn trim_ascii_start(&self) -> &[u8]

Returns a byte slice with leading ASCII whitespace bytes removed.

‘Whitespace’ refers to the definition used by `u8::is_ascii_whitespace`.

##### §Examples

    assert_eq!(b" \t hello world\n".trim_ascii_start(), b"hello world\n");
    assert_eq!(b"  ".trim_ascii_start(), b"");
    assert_eq!(b"".trim_ascii_start(), b"");

1.80.0 (const: 1.80.0) · Source

#### pub const fn trim_ascii_end(&self) -> &[u8]

Returns a byte slice with trailing ASCII whitespace bytes removed.

‘Whitespace’ refers to the definition used by `u8::is_ascii_whitespace`.

##### §Examples

    assert_eq!(b"\r hello world\n ".trim_ascii_end(), b"\r hello world");
    assert_eq!(b"  ".trim_ascii_end(), b"");
    assert_eq!(b"".trim_ascii_end(), b"");

1.80.0 (const: 1.80.0) · Source

#### pub const fn trim_ascii(&self) -> &[u8]

Returns a byte slice with leading and trailing ASCII whitespace bytes removed.

‘Whitespace’ refers to the definition used by `u8::is_ascii_whitespace`.

##### §Examples

    assert_eq!(b"\r hello world\n ".trim_ascii(), b"hello world");
    assert_eq!(b"  ".trim_ascii(), b"");
    assert_eq!(b"".trim_ascii(), b"");

Source§

### impl<T> [T]

1.0.0 (const: 1.39.0) · Source

#### pub const fn len(&self) -> usize

Returns the number of elements in the slice.

##### §Examples

    let a = [1, 2, 3];
    assert_eq!(a.len(), 3);

1.0.0 (const: 1.39.0) · Source

#### pub const fn is_empty(&self) -> bool

Returns `true` if the slice has a length of 0.

##### §Examples

    let a = [1, 2, 3];
    assert!(!a.is_empty());

    let b: &[i32] = &[];
    assert!(b.is_empty());

1.0.0 (const: 1.56.0) · Source

#### pub const fn first(&self) -> Option<&T>

Returns the first element of the slice, or `None` if it is empty.

##### §Examples

    let v = [10, 40, 30];
    assert_eq!(Some(&10), v.first());

    let w: &[i32] = &[];
    assert_eq!(None, w.first());

1.0.0 (const: 1.83.0) · Source

#### pub const fn first_mut(&mut self) -> Option<&mut T>

Returns a mutable reference to the first element of the slice, or `None` if it is empty.

##### §Examples

    let x = &mut [0, 1, 2];

    if let Some(first) = x.first_mut() {
        *first = 5;
    }
    assert_eq!(x, &[5, 1, 2]);

    let y: &mut [i32] = &mut [];
    assert_eq!(None, y.first_mut());

1.5.0 (const: 1.56.0) · Source

#### pub const fn split_first(&self) -> Option<(&T, &[T])>

Returns the first and all the rest of the elements of the slice, or `None` if it is empty.

##### §Examples

    let x = &[0, 1, 2];

    if let Some((first, elements)) = x.split_first() {
        assert_eq!(first, &0);
        assert_eq!(elements, &[1, 2]);
    }

1.5.0 (const: 1.83.0) · Source

#### pub const fn split_first_mut(&mut self) -> Option<(&mut T, &mut [T])>

Returns the first and all the rest of the elements of the slice, or `None` if it is empty.

##### §Examples

    let x = &mut [0, 1, 2];

    if let Some((first, elements)) = x.split_first_mut() {
        *first = 3;
        elements[0] = 4;
        elements[1] = 5;
    }
    assert_eq!(x, &[3, 4, 5]);

1.5.0 (const: 1.56.0) · Source

#### pub const fn split_last(&self) -> Option<(&T, &[T])>

Returns the last and all the rest of the elements of the slice, or `None` if it is empty.

##### §Examples

    let x = &[0, 1, 2];

    if let Some((last, elements)) = x.split_last() {
        assert_eq!(last, &2);
        assert_eq!(elements, &[0, 1]);
    }

1.5.0 (const: 1.83.0) · Source

#### pub const fn split_last_mut(&mut self) -> Option<(&mut T, &mut [T])>

Returns the last and all the rest of the elements of the slice, or `None` if it is empty.

##### §Examples

    let x = &mut [0, 1, 2];

    if let Some((last, elements)) = x.split_last_mut() {
        *last = 3;
        elements[0] = 4;
        elements[1] = 5;
    }
    assert_eq!(x, &[4, 5, 3]);

1.0.0 (const: 1.56.0) · Source

#### pub const fn last(&self) -> Option<&T>

Returns the last element of the slice, or `None` if it is empty.

##### §Examples

    let v = [10, 40, 30];
    assert_eq!(Some(&30), v.last());

    let w: &[i32] = &[];
    assert_eq!(None, w.last());

1.0.0 (const: 1.83.0) · Source

#### pub const fn last_mut(&mut self) -> Option<&mut T>

Returns a mutable reference to the last item in the slice, or `None` if it is empty.

##### §Examples

    let x = &mut [0, 1, 2];

    if let Some(last) = x.last_mut() {
        *last = 10;
    }
    assert_eq!(x, &[0, 1, 10]);

    let y: &mut [i32] = &mut [];
    assert_eq!(None, y.last_mut());

1.77.0 (const: 1.77.0) · Source

#### pub const fn first_chunk<const N: usize>(&self) -> Option<&[T; N]>

Returns an array reference to the first `N` items in the slice.

If the slice is not at least `N` in length, this will return `None`.

##### §Examples

    let u = [10, 40, 30];
    assert_eq!(Some(&[10, 40]), u.first_chunk::<2>());

    let v: &[i32] = &[10];
    assert_eq!(None, v.first_chunk::<2>());

    let w: &[i32] = &[];
    assert_eq!(Some(&[]), w.first_chunk::<0>());

1.77.0 (const: 1.83.0) · Source

#### pub const fn first_chunk_mut<const N: usize>(&mut self) -> Option<&mut [T; N]>

Returns a mutable array reference to the first `N` items in the slice.

If the slice is not at least `N` in length, this will return `None`.

##### §Examples

    let x = &mut [0, 1, 2];

    if let Some(first) = x.first_chunk_mut::<2>() {
        first[0] = 5;
        first[1] = 4;
    }
    assert_eq!(x, &[5, 4, 2]);

    assert_eq!(None, x.first_chunk_mut::<4>());

1.77.0 (const: 1.77.0) · Source

#### pub const fn split_first_chunk<const N: usize>(&self) -> Option<(&[T; N], &[T])>

Returns an array reference to the first `N` items in the slice and the remaining slice.

If the slice is not at least `N` in length, this will return `None`.

##### §Examples

    let x = &[0, 1, 2];

    if let Some((first, elements)) = x.split_first_chunk::<2>() {
        assert_eq!(first, &[0, 1]);
        assert_eq!(elements, &[2]);
    }

    assert_eq!(None, x.split_first_chunk::<4>());

1.77.0 (const: 1.83.0) · Source

#### pub const fn split_first_chunk_mut<const N: usize>( &mut self, ) -> Option<(&mut [T; N], &mut [T])>

Returns a mutable array reference to the first `N` items in the slice and the remaining slice.

If the slice is not at least `N` in length, this will return `None`.

##### §Examples

    let x = &mut [0, 1, 2];

    if let Some((first, elements)) = x.split_first_chunk_mut::<2>() {
        first[0] = 3;
        first[1] = 4;
        elements[0] = 5;
    }
    assert_eq!(x, &[3, 4, 5]);

    assert_eq!(None, x.split_first_chunk_mut::<4>());

1.77.0 (const: 1.77.0) · Source

#### pub const fn split_last_chunk<const N: usize>(&self) -> Option<(&[T], &[T; N])>

Returns an array reference to the last `N` items in the slice and the remaining slice.

If the slice is not at least `N` in length, this will return `None`.

##### §Examples

    let x = &[0, 1, 2];

    if let Some((elements, last)) = x.split_last_chunk::<2>() {
        assert_eq!(elements, &[0]);
        assert_eq!(last, &[1, 2]);
    }

    assert_eq!(None, x.split_last_chunk::<4>());

1.77.0 (const: 1.83.0) · Source

#### pub const fn split_last_chunk_mut<const N: usize>( &mut self, ) -> Option<(&mut [T], &mut [T; N])>

Returns a mutable array reference to the last `N` items in the slice and the remaining slice.

If the slice is not at least `N` in length, this will return `None`.

##### §Examples

    let x = &mut [0, 1, 2];

    if let Some((elements, last)) = x.split_last_chunk_mut::<2>() {
        last[0] = 3;
        last[1] = 4;
        elements[0] = 5;
    }
    assert_eq!(x, &[5, 3, 4]);

    assert_eq!(None, x.split_last_chunk_mut::<4>());

1.77.0 (const: 1.80.0) · Source

#### pub const fn last_chunk<const N: usize>(&self) -> Option<&[T; N]>

Returns an array reference to the last `N` items in the slice.

If the slice is not at least `N` in length, this will return `None`.

##### §Examples

    let u = [10, 40, 30];
    assert_eq!(Some(&[40, 30]), u.last_chunk::<2>());

    let v: &[i32] = &[10];
    assert_eq!(None, v.last_chunk::<2>());

    let w: &[i32] = &[];
    assert_eq!(Some(&[]), w.last_chunk::<0>());

1.77.0 (const: 1.83.0) · Source

#### pub const fn last_chunk_mut<const N: usize>(&mut self) -> Option<&mut [T; N]>

Returns a mutable array reference to the last `N` items in the slice.

If the slice is not at least `N` in length, this will return `None`.

##### §Examples

    let x = &mut [0, 1, 2];

    if let Some(last) = x.last_chunk_mut::<2>() {
        last[0] = 10;
        last[1] = 20;
    }
    assert_eq!(x, &[0, 10, 20]);

    assert_eq!(None, x.last_chunk_mut::<4>());

1.0.0 · Source

#### pub fn get<I>(&self, index: I) -> Option<&I::Output>
where I: SliceIndex<Self>,

Returns a reference to an element or subslice depending on the type of index.

- If given a position, returns a reference to the element at that position or `None` if out of bounds.
- If given a range, returns the subslice corresponding to that range, or `None` if out of bounds.

##### §Examples

    let v = [10, 40, 30];
    assert_eq!(Some(&40), v.get(1));
    assert_eq!(Some(&[10, 40][..]), v.get(0..2));
    assert_eq!(None, v.get(3));
    assert_eq!(None, v.get(0..4));

1.0.0 · Source

#### pub fn get_mut<I>(&mut self, index: I) -> Option<&mut I::Output>
where I: SliceIndex<Self>,

Returns a mutable reference to an element or subslice depending on the type of index (see `get`) or `None` if the index is out of bounds.

##### §Examples

    let x = &mut [0, 1, 2];

    if let Some(elem) = x.get_mut(1) {
        *elem = 42;
    }
    assert_eq!(x, &[0, 42, 2]);

1.0.0 · Source

#### pub unsafe fn get_unchecked<I>(&self, index: I) -> &I::Output
where I: SliceIndex<Self>,

Returns a reference to an element or subslice, without doing bounds checking.

For a safe alternative see `get`.

##### §Safety

Calling this method with an out-of-bounds index is undefined behavior even if the resulting reference is not used.

You can think of this like `.get(index).unwrap_unchecked()`. It’s UB to call `.get_unchecked(len)`, even if you immediately convert to a pointer. And it’s UB to call `.get_unchecked(..len + 1)`, `.get_unchecked(..=len)`, or similar.

##### §Examples

    let x = &[1, 2, 4];

    unsafe {
        assert_eq!(x.get_unchecked(1), &2);
    }

1.0.0 · Source

#### pub unsafe fn get_unchecked_mut<I>(&mut self, index: I) -> &mut I::Output
where I: SliceIndex<Self>,

Returns a mutable reference to an element or subslice, without doing bounds checking.

For a safe alternative see `get_mut`.

##### §Safety

Calling this method with an out-of-bounds index is undefined behavior even if the resulting reference is not used.

You can think of this like `.get_mut(index).unwrap_unchecked()`. It’s UB to call `.get_unchecked_mut(len)`, even if you immediately convert to a pointer. And it’s UB to call `.get_unchecked_mut(..len + 1)`, `.get_unchecked_mut(..=len)`, or similar.

##### §Examples

    let x = &mut [1, 2, 4];

    unsafe {
        let elem = x.get_unchecked_mut(1);
        *elem = 13;
    }
    assert_eq!(x, &[1, 13, 4]);

1.0.0 (const: 1.32.0) · Source

#### pub const fn as_ptr(&self) -> *const T

Returns a raw pointer to the slice’s buffer.

The caller must ensure that the slice outlives the pointer this function returns, or else it will end up dangling.

The caller must also ensure that the memory the pointer (non-transitively) points to is never written to (except inside an `UnsafeCell`) using this pointer or any pointer derived from it. If you need to mutate the contents of the slice, use `as_mut_ptr`.

Modifying the container referenced by this slice may cause its buffer to be reallocated, which would also make any pointers to it invalid.

##### §Examples

    let x = &[1, 2, 4];
    let x_ptr = x.as_ptr();

    unsafe {
        for i in 0..x.len() {
            assert_eq!(x.get_unchecked(i), &*x_ptr.add(i));
        }
    }

1.0.0 (const: 1.61.0) · Source

#### pub const fn as_mut_ptr(&mut self) -> *mut T

Returns an unsafe mutable pointer to the slice’s buffer.

The caller must ensure that the slice outlives the pointer this function returns, or else it will end up dangling.

Modifying the container referenced by this slice may cause its buffer to be reallocated, which would also make any pointers to it invalid.

##### §Examples

    let x = &mut [1, 2, 4];
    let x_ptr = x.as_mut_ptr();

    unsafe {
        for i in 0..x.len() {
            *x_ptr.add(i) += 2;
        }
    }
    assert_eq!(x, &[3, 4, 6]);

1.48.0 (const: 1.61.0) · Source

#### pub const fn as_ptr_range(&self) -> Range<*const T> ⓘ

Returns the two raw pointers spanning the slice.

The returned range is half-open, which means that the end pointer points one past the last element of the slice. This way, an empty slice is represented by two equal pointers, and the difference between the two pointers represents the size of the slice.

See `as_ptr` for warnings on using these pointers. The end pointer requires extra caution, as it does not point to a valid element in the slice.

This function is useful for interacting with foreign interfaces which use two pointers to refer to a range of elements in memory, as is common in C++.

It can also be useful to check if a pointer to an element refers to an element of this slice:

    let a = [1, 2, 3];
    let x = &a[1] as *const _;
    let y = &5 as *const _;

    assert!(a.as_ptr_range().contains(&x));
    assert!(!a.as_ptr_range().contains(&y));

1.48.0 (const: 1.61.0) · Source

#### pub const fn as_mut_ptr_range(&mut self) -> Range<*mut T> ⓘ

Returns the two unsafe mutable pointers spanning the slice.

The returned range is half-open, which means that the end pointer points one past the last element of the slice. This way, an empty slice is represented by two equal pointers, and the difference between the two pointers represents the size of the slice.

See `as_mut_ptr` for warnings on using these pointers. The end pointer requires extra caution, as it does not point to a valid element in the slice.

This function is useful for interacting with foreign interfaces which use two pointers to refer to a range of elements in memory, as is common in C++.

Source

#### pub const fn as_array<const N: usize>(&self) -> Option<&[T; N]>

🔬This is a nightly-only experimental API. (`slice_as_array` #133508)

Gets a reference to the underlying array.

If `N` is not exactly equal to the length of `self`, then this method returns `None`.

Source

#### pub const fn as_mut_array<const N: usize>(&mut self) -> Option<&mut [T; N]>

🔬This is a nightly-only experimental API. (`slice_as_array` #133508)

Gets a mutable reference to the slice’s underlying array.

If `N` is not exactly equal to the length of `self`, then this method returns `None`.

1.0.0 (const: 1.85.0) · Source

#### pub const fn swap(&mut self, a: usize, b: usize)

Swaps two elements in the slice.

If `a` equals to `b`, it’s guaranteed that elements won’t change value.

##### §Arguments

- a - The index of the first element
- b - The index of the second element

##### §Panics

Panics if `a` or `b` are out of bounds.

##### §Examples

    let mut v = ["a", "b", "c", "d", "e"];
    v.swap(2, 4);
    assert!(v == ["a", "b", "e", "d", "c"]);

Source

#### pub const unsafe fn swap_unchecked(&mut self, a: usize, b: usize)

🔬This is a nightly-only experimental API. (`slice_swap_unchecked` #88539)

Swaps two elements in the slice, without doing bounds checking.

For a safe alternative see `swap`.

##### §Arguments

- a - The index of the first element
- b - The index of the second element

##### §Safety

Calling this method with an out-of-bounds index is undefined behavior. The caller has to ensure that `a < self.len()` and `b < self.len()`.

##### §Examples

    #![feature(slice_swap_unchecked)]

    let mut v = ["a", "b", "c", "d"];
    // SAFETY: we know that 1 and 3 are both indices of the slice
    unsafe { v.swap_unchecked(1, 3) };
    assert!(v == ["a", "d", "c", "b"]);

1.0.0 (const: unstable) · Source

#### pub fn reverse(&mut self)

Reverses the order of elements in the slice, in place.

##### §Examples

    let mut v = [1, 2, 3];
    v.reverse();
    assert!(v == [3, 2, 1]);

1.0.0 (const: unstable) · Source

#### pub fn iter(&self) -> Iter<'_, T> ⓘ

Returns an iterator over the slice.

The iterator yields all items from start to end.

##### §Examples

    let x = &[1, 2, 4];
    let mut iterator = x.iter();

    assert_eq!(iterator.next(), Some(&1));
    assert_eq!(iterator.next(), Some(&2));
    assert_eq!(iterator.next(), Some(&4));
    assert_eq!(iterator.next(), None);

1.0.0 (const: unstable) · Source

#### pub fn iter_mut(&mut self) -> IterMut<'_, T> ⓘ

Returns an iterator that allows modifying each value.

The iterator yields all items from start to end.

##### §Examples

    let x = &mut [1, 2, 4];
    for elem in x.iter_mut() {
        *elem += 2;
    }
    assert_eq!(x, &[3, 4, 6]);

1.0.0 (const: unstable) · Source

#### pub fn windows(&self, size: usize) -> Windows<'_, T> ⓘ

Returns an iterator over all contiguous windows of length `size`. The windows overlap. If the slice is shorter than `size`, the iterator returns no values.

##### §Panics

Panics if `size` is zero.

##### §Examples

    let slice = ['l', 'o', 'r', 'e', 'm'];
    let mut iter = slice.windows(3);
    assert_eq!(iter.next().unwrap(), &['l', 'o', 'r']);
    assert_eq!(iter.next().unwrap(), &['o', 'r', 'e']);
    assert_eq!(iter.next().unwrap(), &['r', 'e', 'm']);
    assert!(iter.next().is_none());

If the slice is shorter than `size`:

    let slice = ['f', 'o', 'o'];
    let mut iter = slice.windows(4);
    assert!(iter.next().is_none());

Because the Iterator trait cannot represent the required lifetimes, there is no `windows_mut` analog to `windows`; `[0,1,2].windows_mut(2).collect()` would violate the rules of references (though a LendingIterator analog is possible). You can sometimes use `Cell::as_slice_of_cells` in conjunction with `windows` instead:

    use std::cell::Cell;

    let mut array = ['R', 'u', 's', 't', ' ', '2', '0', '1', '5'];
    let slice = &mut array[..];
    let slice_of_cells: &[Cell<char>] = Cell::from_mut(slice).as_slice_of_cells();
    for w in slice_of_cells.windows(3) {
        Cell::swap(&w[0], &w[2]);
    }
    assert_eq!(array, ['s', 't', ' ', '2', '0', '1', '5', 'u', 'R']);

1.0.0 (const: unstable) · Source

#### pub fn chunks(&self, chunk_size: usize) -> Chunks<'_, T> ⓘ

Returns an iterator over `chunk_size` elements of the slice at a time, starting at the beginning of the slice.

The chunks are slices and do not overlap. If `chunk_size` does not divide the length of the slice, then the last chunk will not have length `chunk_size`.

See `chunks_exact` for a variant of this iterator that returns chunks of always exactly `chunk_size` elements, and `rchunks` for the same iterator but starting at the end of the slice.

##### §Panics

Panics if `chunk_size` is zero.

##### §Examples

    let slice = ['l', 'o', 'r', 'e', 'm'];
    let mut iter = slice.chunks(2);
    assert_eq!(iter.next().unwrap(), &['l', 'o']);
    assert_eq!(iter.next().unwrap(), &['r', 'e']);
    assert_eq!(iter.next().unwrap(), &['m']);
    assert!(iter.next().is_none());

1.0.0 (const: unstable) · Source

#### pub fn chunks_mut(&mut self, chunk_size: usize) -> ChunksMut<'_, T> ⓘ

Returns an iterator over `chunk_size` elements of the slice at a time, starting at the beginning of the slice.

The chunks are mutable slices, and do not overlap. If `chunk_size` does not divide the length of the slice, then the last chunk will not have length `chunk_size`.

See `chunks_exact_mut` for a variant of this iterator that returns chunks of always exactly `chunk_size` elements, and `rchunks_mut` for the same iterator but starting at the end of the slice.

##### §Panics

Panics if `chunk_size` is zero.

##### §Examples

    let v = &mut [0, 0, 0, 0, 0];
    let mut count = 1;

    for chunk in v.chunks_mut(2) {
        for elem in chunk.iter_mut() {
            *elem += count;
        }
        count += 1;
    }
    assert_eq!(v, &[1, 1, 2, 2, 3]);

1.31.0 (const: unstable) · Source

#### pub fn chunks_exact(&self, chunk_size: usize) -> ChunksExact<'_, T> ⓘ

Returns an iterator over `chunk_size` elements of the slice at a time, starting at the beginning of the slice.

The chunks are slices and do not overlap. If `chunk_size` does not divide the length of the slice, then the last up to `chunk_size-1` elements will be omitted and can be retrieved from the `remainder` function of the iterator.

Due to each chunk having exactly `chunk_size` elements, the compiler can often optimize the resulting code better than in the case of `chunks`.

See `chunks` for a variant of this iterator that also returns the remainder as a smaller chunk, and `rchunks_exact` for the same iterator but starting at the end of the slice.

##### §Panics

Panics if `chunk_size` is zero.

##### §Examples

    let slice = ['l', 'o', 'r', 'e', 'm'];
    let mut iter = slice.chunks_exact(2);
    assert_eq!(iter.next().unwrap(), &['l', 'o']);
    assert_eq!(iter.next().unwrap(), &['r', 'e']);
    assert!(iter.next().is_none());
    assert_eq!(iter.remainder(), &['m']);

1.31.0 (const: unstable) · Source

#### pub fn chunks_exact_mut(&mut self, chunk_size: usize) -> ChunksExactMut<'_, T> ⓘ

Returns an iterator over `chunk_size` elements of the slice at a time, starting at the beginning of the slice.

The chunks are mutable slices, and do not overlap. If `chunk_size` does not divide the length of the slice, then the last up to `chunk_size-1` elements will be omitted and can be retrieved from the `into_remainder` function of the iterator.

Due to each chunk having exactly `chunk_size` elements, the compiler can often optimize the resulting code better than in the case of `chunks_mut`.

See `chunks_mut` for a variant of this iterator that also returns the remainder as a smaller chunk, and `rchunks_exact_mut` for the same iterator but starting at the end of the slice.

##### §Panics

Panics if `chunk_size` is zero.

##### §Examples

    let v = &mut [0, 0, 0, 0, 0];
    let mut count = 1;

    for chunk in v.chunks_exact_mut(2) {
        for elem in chunk.iter_mut() {
            *elem += count;
        }
        count += 1;
    }
    assert_eq!(v, &[1, 1, 2, 2, 0]);

1.88.0 (const: 1.88.0) · Source

#### pub const unsafe fn as_chunks_unchecked<const N: usize>(&self) -> &[[T; N]]

Splits the slice into a slice of `N`-element arrays, assuming that there’s no remainder.

This is the inverse operation to `as_flattened`.

As this is `unsafe`, consider whether you could use `as_chunks` or `as_rchunks` instead, perhaps via something like `if let (chunks, []) = slice.as_chunks()` or `let (chunks, []) = slice.as_chunks() else { unreachable!() };`.

##### §Safety

This may only be called when

- The slice splits exactly into `N`-element chunks (aka `self.len() % N == 0`).
- `N != 0`.

##### §Examples

    let slice: &[char] = &['l', 'o', 'r', 'e', 'm', '!'];
    let chunks: &[[char; 1]] =
        // SAFETY: 1-element chunks never have remainder
        unsafe { slice.as_chunks_unchecked() };
    assert_eq!(chunks, &[['l'], ['o'], ['r'], ['e'], ['m'], ['!']]);
    let chunks: &[[char; 3]] =
        // SAFETY: The slice length (6) is a multiple of 3
        unsafe { slice.as_chunks_unchecked() };
    assert_eq!(chunks, &[['l', 'o', 'r'], ['e', 'm', '!']]);

    // These would be unsound:
    // let chunks: &[[_; 5]] = slice.as_chunks_unchecked() // The slice length is not a multiple of 5
    // let chunks: &[[_; 0]] = slice.as_chunks_unchecked() // Zero-length chunks are never allowed

1.88.0 (const: 1.88.0) · Source

#### pub const fn as_chunks<const N: usize>(&self) -> (&[[T; N]], &[T])

Splits the slice into a slice of `N`-element arrays, starting at the beginning of the slice, and a remainder slice with length strictly less than `N`.

The remainder is meaningful in the division sense. Given `let (chunks, remainder) = slice.as_chunks()`, then:

- `chunks.len()` equals `slice.len() / N`,
- `remainder.len()` equals `slice.len() % N`, and
- `slice.len()` equals `chunks.len() * N + remainder.len()`.

You can flatten the chunks back into a slice-of-`T` with `as_flattened`.

##### §Panics

Panics if `N` is zero.

Note that this check is against a const generic parameter, not a runtime value, and thus a particular monomorphization will either always panic or it will never panic.

##### §Examples

    let slice = ['l', 'o', 'r', 'e', 'm'];
    let (chunks, remainder) = slice.as_chunks();
    assert_eq!(chunks, &[['l', 'o'], ['r', 'e']]);
    assert_eq!(remainder, &['m']);

If you expect the slice to be an exact multiple, you can combine `let`-`else` with an empty slice pattern:

    let slice = ['R', 'u', 's', 't'];
    let (chunks, []) = slice.as_chunks::<2>() else {
        panic!("slice didn't have even length")
    };
    assert_eq!(chunks, &[['R', 'u'], ['s', 't']]);

1.88.0 (const: 1.88.0) · Source

#### pub const fn as_rchunks<const N: usize>(&self) -> (&[T], &[[T; N]])

Splits the slice into a slice of `N`-element arrays, starting at the end of the slice, and a remainder slice with length strictly less than `N`.

The remainder is meaningful in the division sense. Given `let (remainder, chunks) = slice.as_rchunks()`, then:

- `remainder.len()` equals `slice.len() % N`,
- `chunks.len()` equals `slice.len() / N`, and
- `slice.len()` equals `chunks.len() * N + remainder.len()`.

You can flatten the chunks back into a slice-of-`T` with `as_flattened`.

##### §Panics

Panics if `N` is zero.

Note that this check is against a const generic parameter, not a runtime value, and thus a particular monomorphization will either always panic or it will never panic.

##### §Examples

    let slice = ['l', 'o', 'r', 'e', 'm'];
    let (remainder, chunks) = slice.as_rchunks();
    assert_eq!(remainder, &['l']);
    assert_eq!(chunks, &[['o', 'r'], ['e', 'm']]);

Source

#### pub const fn array_chunks<const N: usize>(&self) -> ArrayChunks<'_, T, N> ⓘ

🔬This is a nightly-only experimental API. (`array_chunks` #74985)

Returns an iterator over `N` elements of the slice at a time, starting at the beginning of the slice.

The chunks are array references and do not overlap. If `N` does not divide the length of the slice, then the last up to `N-1` elements will be omitted and can be retrieved from the `remainder` function of the iterator.

This method is the const generic equivalent of `chunks_exact`.

##### §Panics

Panics if `N` is zero. This check will most probably get changed to a compile time error before this method gets stabilized.

##### §Examples

    #![feature(array_chunks)]
    let slice = ['l', 'o', 'r', 'e', 'm'];
    let mut iter = slice.array_chunks();
    assert_eq!(iter.next().unwrap(), &['l', 'o']);
    assert_eq!(iter.next().unwrap(), &['r', 'e']);
    assert!(iter.next().is_none());
    assert_eq!(iter.remainder(), &['m']);

1.88.0 (const: 1.88.0) · Source

#### pub const unsafe fn as_chunks_unchecked_mut<const N: usize>( &mut self, ) -> &mut [[T; N]]

Splits the slice into a slice of `N`-element arrays, assuming that there’s no remainder.

This is the inverse operation to `as_flattened_mut`.

As this is `unsafe`, consider whether you could use `as_chunks_mut` or `as_rchunks_mut` instead, perhaps via something like `if let (chunks, []) = slice.as_chunks_mut()` or `let (chunks, []) = slice.as_chunks_mut() else { unreachable!() };`.

##### §Safety

This may only be called when

- The slice splits exactly into `N`-element chunks (aka `self.len() % N == 0`).
- `N != 0`.

##### §Examples

    let slice: &mut [char] = &mut ['l', 'o', 'r', 'e', 'm', '!'];
    let chunks: &mut [[char; 1]] =
        // SAFETY: 1-element chunks never have remainder
        unsafe { slice.as_chunks_unchecked_mut() };
    chunks[0] = ['L'];
    assert_eq!(chunks, &[['L'], ['o'], ['r'], ['e'], ['m'], ['!']]);
    let chunks: &mut [[char; 3]] =
        // SAFETY: The slice length (6) is a multiple of 3
        unsafe { slice.as_chunks_unchecked_mut() };
    chunks[1] = ['a', 'x', '?'];
    assert_eq!(slice, &['L', 'o', 'r', 'a', 'x', '?']);

    // These would be unsound:
    // let chunks: &[[_; 5]] = slice.as_chunks_unchecked_mut() // The slice length is not a multiple of 5
    // let chunks: &[[_; 0]] = slice.as_chunks_unchecked_mut() // Zero-length chunks are never allowed

1.88.0 (const: 1.88.0) · Source

#### pub const fn as_chunks_mut<const N: usize>( &mut self, ) -> (&mut [[T; N]], &mut [T])

Splits the slice into a slice of `N`-element arrays, starting at the beginning of the slice, and a remainder slice with length strictly less than `N`.

The remainder is meaningful in the division sense. Given `let (chunks, remainder) = slice.as_chunks_mut()`, then:

- `chunks.len()` equals `slice.len() / N`,
- `remainder.len()` equals `slice.len() % N`, and
- `slice.len()` equals `chunks.len() * N + remainder.len()`.

You can flatten the chunks back into a slice-of-`T` with `as_flattened_mut`.

##### §Panics

Panics if `N` is zero.

Note that this check is against a const generic parameter, not a runtime value, and thus a particular monomorphization will either always panic or it will never panic.

##### §Examples

    let v = &mut [0, 0, 0, 0, 0];
    let mut count = 1;

    let (chunks, remainder) = v.as_chunks_mut();
    remainder[0] = 9;
    for chunk in chunks {
        *chunk = [count; 2];
        count += 1;
    }
    assert_eq!(v, &[1, 1, 2, 2, 9]);

1.88.0 (const: 1.88.0) · Source

#### pub const fn as_rchunks_mut<const N: usize>( &mut self, ) -> (&mut [T], &mut [[T; N]])

Splits the slice into a slice of `N`-element arrays, starting at the end of the slice, and a remainder slice with length strictly less than `N`.

The remainder is meaningful in the division sense. Given `let (remainder, chunks) = slice.as_rchunks_mut()`, then:

- `remainder.len()` equals `slice.len() % N`,
- `chunks.len()` equals `slice.len() / N`, and
- `slice.len()` equals `chunks.len() * N + remainder.len()`.

You can flatten the chunks back into a slice-of-`T` with `as_flattened_mut`.

##### §Panics

Panics if `N` is zero.

Note that this check is against a const generic parameter, not a runtime value, and thus a particular monomorphization will either always panic or it will never panic.

##### §Examples

    let v = &mut [0, 0, 0, 0, 0];
    let mut count = 1;

    let (remainder, chunks) = v.as_rchunks_mut();
    remainder[0] = 9;
    for chunk in chunks {
        *chunk = [count; 2];
        count += 1;
    }
    assert_eq!(v, &[9, 1, 1, 2, 2]);

Source

#### pub const fn array_chunks_mut<const N: usize>( &mut self, ) -> ArrayChunksMut<'_, T, N> ⓘ

🔬This is a nightly-only experimental API. (`array_chunks` #74985)

Returns an iterator over `N` elements of the slice at a time, starting at the beginning of the slice.

The chunks are mutable array references and do not overlap. If `N` does not divide the length of the slice, then the last up to `N-1` elements will be omitted and can be retrieved from the `into_remainder` function of the iterator.

This method is the const generic equivalent of `chunks_exact_mut`.

##### §Panics

Panics if `N` is zero. This check will most probably get changed to a compile time error before this method gets stabilized.

##### §Examples

    #![feature(array_chunks)]
    let v = &mut [0, 0, 0, 0, 0];
    let mut count = 1;

    for chunk in v.array_chunks_mut() {
        *chunk = [count; 2];
        count += 1;
    }
    assert_eq!(v, &[1, 1, 2, 2, 0]);

Source

#### pub const fn array_windows<const N: usize>(&self) -> ArrayWindows<'_, T, N> ⓘ

🔬This is a nightly-only experimental API. (`array_windows` #75027)

Returns an iterator over overlapping windows of `N` elements of a slice, starting at the beginning of the slice.

This is the const generic equivalent of `windows`.

If `N` is greater than the size of the slice, it will return no windows.

##### §Panics

Panics if `N` is zero. This check will most probably get changed to a compile time error before this method gets stabilized.

##### §Examples

    #![feature(array_windows)]
    let slice = [0, 1, 2, 3];
    let mut iter = slice.array_windows();
    assert_eq!(iter.next().unwrap(), &[0, 1]);
    assert_eq!(iter.next().unwrap(), &[1, 2]);
    assert_eq!(iter.next().unwrap(), &[2, 3]);
    assert!(iter.next().is_none());

1.31.0 (const: unstable) · Source

#### pub fn rchunks(&self, chunk_size: usize) -> RChunks<'_, T> ⓘ

Returns an iterator over `chunk_size` elements of the slice at a time, starting at the end of the slice.

The chunks are slices and do not overlap. If `chunk_size` does not divide the length of the slice, then the last chunk will not have length `chunk_size`.

See `rchunks_exact` for a variant of this iterator that returns chunks of always exactly `chunk_size` elements, and `chunks` for the same iterator but starting at the beginning of the slice.

##### §Panics

Panics if `chunk_size` is zero.

##### §Examples

    let slice = ['l', 'o', 'r', 'e', 'm'];
    let mut iter = slice.rchunks(2);
    assert_eq!(iter.next().unwrap(), &['e', 'm']);
    assert_eq!(iter.next().unwrap(), &['o', 'r']);
    assert_eq!(iter.next().unwrap(), &['l']);
    assert!(iter.next().is_none());

1.31.0 (const: unstable) · Source

#### pub fn rchunks_mut(&mut self, chunk_size: usize) -> RChunksMut<'_, T> ⓘ

Returns an iterator over `chunk_size` elements of the slice at a time, starting at the end of the slice.

The chunks are mutable slices, and do not overlap. If `chunk_size` does not divide the length of the slice, then the last chunk will not have length `chunk_size`.

See `rchunks_exact_mut` for a variant of this iterator that returns chunks of always exactly `chunk_size` elements, and `chunks_mut` for the same iterator but starting at the beginning of the slice.

##### §Panics

Panics if `chunk_size` is zero.

##### §Examples

    let v = &mut [0, 0, 0, 0, 0];
    let mut count = 1;

    for chunk in v.rchunks_mut(2) {
        for elem in chunk.iter_mut() {
            *elem += count;
        }
        count += 1;
    }
    assert_eq!(v, &[3, 2, 2, 1, 1]);

1.31.0 (const: unstable) · Source

#### pub fn rchunks_exact(&self, chunk_size: usize) -> RChunksExact<'_, T> ⓘ

Returns an iterator over `chunk_size` elements of the slice at a time, starting at the end of the slice.

The chunks are slices and do not overlap. If `chunk_size` does not divide the length of the slice, then the last up to `chunk_size-1` elements will be omitted and can be retrieved from the `remainder` function of the iterator.

Due to each chunk having exactly `chunk_size` elements, the compiler can often optimize the resulting code better than in the case of `rchunks`.

See `rchunks` for a variant of this iterator that also returns the remainder as a smaller chunk, and `chunks_exact` for the same iterator but starting at the beginning of the slice.

##### §Panics

Panics if `chunk_size` is zero.

##### §Examples

    let slice = ['l', 'o', 'r', 'e', 'm'];
    let mut iter = slice.rchunks_exact(2);
    assert_eq!(iter.next().unwrap(), &['e', 'm']);
    assert_eq!(iter.next().unwrap(), &['o', 'r']);
    assert!(iter.next().is_none());
    assert_eq!(iter.remainder(), &['l']);

1.31.0 (const: unstable) · Source

#### pub fn rchunks_exact_mut(&mut self, chunk_size: usize) -> RChunksExactMut<'_, T> ⓘ

Returns an iterator over `chunk_size` elements of the slice at a time, starting at the end of the slice.

The chunks are mutable slices, and do not overlap. If `chunk_size` does not divide the length of the slice, then the last up to `chunk_size-1` elements will be omitted and can be retrieved from the `into_remainder` function of the iterator.

Due to each chunk having exactly `chunk_size` elements, the compiler can often optimize the resulting code better than in the case of `chunks_mut`.

See `rchunks_mut` for a variant of this iterator that also returns the remainder as a smaller chunk, and `chunks_exact_mut` for the same iterator but starting at the beginning of the slice.

##### §Panics

Panics if `chunk_size` is zero.

##### §Examples

    let v = &mut [0, 0, 0, 0, 0];
    let mut count = 1;

    for chunk in v.rchunks_exact_mut(2) {
        for elem in chunk.iter_mut() {
            *elem += count;
        }
        count += 1;
    }
    assert_eq!(v, &[0, 2, 2, 1, 1]);

1.77.0 (const: unstable) · Source

#### pub fn chunk_by<F>(&self, pred: F) -> ChunkBy<'_, T, F> ⓘ
where F: FnMut(&T, &T) -> bool,

Returns an iterator over the slice producing non-overlapping runs of elements using the predicate to separate them.

The predicate is called for every pair of consecutive elements, meaning that it is called on `slice[0]` and `slice[1]`, followed by `slice[1]` and `slice[2]`, and so on.

##### §Examples

    let slice = &[1, 1, 1, 3, 3, 2, 2, 2];

    let mut iter = slice.chunk_by(|a, b| a == b);

    assert_eq!(iter.next(), Some(&[1, 1, 1][..]));
    assert_eq!(iter.next(), Some(&[3, 3][..]));
    assert_eq!(iter.next(), Some(&[2, 2, 2][..]));
    assert_eq!(iter.next(), None);

This method can be used to extract the sorted subslices:

    let slice = &[1, 1, 2, 3, 2, 3, 2, 3, 4];

    let mut iter = slice.chunk_by(|a, b| a <= b);

    assert_eq!(iter.next(), Some(&[1, 1, 2, 3][..]));
    assert_eq!(iter.next(), Some(&[2, 3][..]));
    assert_eq!(iter.next(), Some(&[2, 3, 4][..]));
    assert_eq!(iter.next(), None);

1.77.0 (const: unstable) · Source

#### pub fn chunk_by_mut<F>(&mut self, pred: F) -> ChunkByMut<'_, T, F> ⓘ
where F: FnMut(&T, &T) -> bool,

Returns an iterator over the slice producing non-overlapping mutable runs of elements using the predicate to separate them.

The predicate is called for every pair of consecutive elements, meaning that it is called on `slice[0]` and `slice[1]`, followed by `slice[1]` and `slice[2]`, and so on.

##### §Examples

    let slice = &mut [1, 1, 1, 3, 3, 2, 2, 2];

    let mut iter = slice.chunk_by_mut(|a, b| a == b);

    assert_eq!(iter.next(), Some(&mut [1, 1, 1][..]));
    assert_eq!(iter.next(), Some(&mut [3, 3][..]));
    assert_eq!(iter.next(), Some(&mut [2, 2, 2][..]));
    assert_eq!(iter.next(), None);

This method can be used to extract the sorted subslices:

    let slice = &mut [1, 1, 2, 3, 2, 3, 2, 3, 4];

    let mut iter = slice.chunk_by_mut(|a, b| a <= b);

    assert_eq!(iter.next(), Some(&mut [1, 1, 2, 3][..]));
    assert_eq!(iter.next(), Some(&mut [2, 3][..]));
    assert_eq!(iter.next(), Some(&mut [2, 3, 4][..]));
    assert_eq!(iter.next(), None);

1.0.0 (const: 1.71.0) · Source

#### pub const fn split_at(&self, mid: usize) -> (&[T], &[T])

Divides one slice into two at an index.

The first will contain all indices from `[0, mid)` (excluding the index `mid` itself) and the second will contain all indices from `[mid, len)` (excluding the index `len` itself).

##### §Panics

Panics if `mid > len`. For a non-panicking alternative see `split_at_checked`.

##### §Examples

    let v = ['a', 'b', 'c'];

    {
       let (left, right) = v.split_at(0);
       assert_eq!(left, []);
       assert_eq!(right, ['a', 'b', 'c']);
    }

    {
        let (left, right) = v.split_at(2);
        assert_eq!(left, ['a', 'b']);
        assert_eq!(right, ['c']);
    }

    {
        let (left, right) = v.split_at(3);
        assert_eq!(left, ['a', 'b', 'c']);
        assert_eq!(right, []);
    }

1.0.0 (const: 1.83.0) · Source

#### pub const fn split_at_mut(&mut self, mid: usize) -> (&mut [T], &mut [T])

Divides one mutable slice into two at an index.

The first will contain all indices from `[0, mid)` (excluding the index `mid` itself) and the second will contain all indices from `[mid, len)` (excluding the index `len` itself).

##### §Panics

Panics if `mid > len`. For a non-panicking alternative see `split_at_mut_checked`.

##### §Examples

    let mut v = [1, 0, 3, 0, 5, 6];
    let (left, right) = v.split_at_mut(2);
    assert_eq!(left, [1, 0]);
    assert_eq!(right, [3, 0, 5, 6]);
    left[1] = 2;
    right[1] = 4;
    assert_eq!(v, [1, 2, 3, 4, 5, 6]);

1.79.0 (const: 1.77.0) · Source

#### pub const unsafe fn split_at_unchecked(&self, mid: usize) -> (&[T], &[T])

Divides one slice into two at an index, without doing bounds checking.

The first will contain all indices from `[0, mid)` (excluding the index `mid` itself) and the second will contain all indices from `[mid, len)` (excluding the index `len` itself).

For a safe alternative see `split_at`.

##### §Safety

Calling this method with an out-of-bounds index is undefined behavior even if the resulting reference is not used. The caller has to ensure that `0 <= mid <= self.len()`.

##### §Examples

    let v = ['a', 'b', 'c'];

    unsafe {
       let (left, right) = v.split_at_unchecked(0);
       assert_eq!(left, []);
       assert_eq!(right, ['a', 'b', 'c']);
    }

    unsafe {
        let (left, right) = v.split_at_unchecked(2);
        assert_eq!(left, ['a', 'b']);
        assert_eq!(right, ['c']);
    }

    unsafe {
        let (left, right) = v.split_at_unchecked(3);
        assert_eq!(left, ['a', 'b', 'c']);
        assert_eq!(right, []);
    }

1.79.0 (const: 1.83.0) · Source

#### pub const unsafe fn split_at_mut_unchecked( &mut self, mid: usize, ) -> (&mut [T], &mut [T])

Divides one mutable slice into two at an index, without doing bounds checking.

The first will contain all indices from `[0, mid)` (excluding the index `mid` itself) and the second will contain all indices from `[mid, len)` (excluding the index `len` itself).

For a safe alternative see `split_at_mut`.

##### §Safety

Calling this method with an out-of-bounds index is undefined behavior even if the resulting reference is not used. The caller has to ensure that `0 <= mid <= self.len()`.

##### §Examples

    let mut v = [1, 0, 3, 0, 5, 6];
    // scoped to restrict the lifetime of the borrows
    unsafe {
        let (left, right) = v.split_at_mut_unchecked(2);
        assert_eq!(left, [1, 0]);
        assert_eq!(right, [3, 0, 5, 6]);
        left[1] = 2;
        right[1] = 4;
    }
    assert_eq!(v, [1, 2, 3, 4, 5, 6]);

1.80.0 (const: 1.80.0) · Source

#### pub const fn split_at_checked(&self, mid: usize) -> Option<(&[T], &[T])>

Divides one slice into two at an index, returning `None` if the slice is too short.

If `mid ≤ len` returns a pair of slices where the first will contain all indices from `[0, mid)` (excluding the index `mid` itself) and the second will contain all indices from `[mid, len)` (excluding the index `len` itself).

Otherwise, if `mid > len`, returns `None`.

##### §Examples

    let v = [1, -2, 3, -4, 5, -6];

    {
       let (left, right) = v.split_at_checked(0).unwrap();
       assert_eq!(left, []);
       assert_eq!(right, [1, -2, 3, -4, 5, -6]);
    }

    {
        let (left, right) = v.split_at_checked(2).unwrap();
        assert_eq!(left, [1, -2]);
        assert_eq!(right, [3, -4, 5, -6]);
    }

    {
        let (left, right) = v.split_at_checked(6).unwrap();
        assert_eq!(left, [1, -2, 3, -4, 5, -6]);
        assert_eq!(right, []);
    }

    assert_eq!(None, v.split_at_checked(7));

1.80.0 (const: 1.83.0) · Source

#### pub const fn split_at_mut_checked( &mut self, mid: usize, ) -> Option<(&mut [T], &mut [T])>

Divides one mutable slice into two at an index, returning `None` if the slice is too short.

If `mid ≤ len` returns a pair of slices where the first will contain all indices from `[0, mid)` (excluding the index `mid` itself) and the second will contain all indices from `[mid, len)` (excluding the index `len` itself).

Otherwise, if `mid > len`, returns `None`.

##### §Examples

    let mut v = [1, 0, 3, 0, 5, 6];

    if let Some((left, right)) = v.split_at_mut_checked(2) {
        assert_eq!(left, [1, 0]);
        assert_eq!(right, [3, 0, 5, 6]);
        left[1] = 2;
        right[1] = 4;
    }
    assert_eq!(v, [1, 2, 3, 4, 5, 6]);

    assert_eq!(None, v.split_at_mut_checked(7));

1.0.0 · Source

#### pub fn split<F>(&self, pred: F) -> Split<'_, T, F> ⓘ
where F: FnMut(&T) -> bool,

Returns an iterator over subslices separated by elements that match `pred`. The matched element is not contained in the subslices.

##### §Examples

    let slice = [10, 40, 33, 20];
    let mut iter = slice.split(|num| num % 3 == 0);

    assert_eq!(iter.next().unwrap(), &[10, 40]);
    assert_eq!(iter.next().unwrap(), &[20]);
    assert!(iter.next().is_none());

If the first element is matched, an empty slice will be the first item returned by the iterator. Similarly, if the last element in the slice is matched, an empty slice will be the last item returned by the iterator:

    let slice = [10, 40, 33];
    let mut iter = slice.split(|num| num % 3 == 0);

    assert_eq!(iter.next().unwrap(), &[10, 40]);
    assert_eq!(iter.next().unwrap(), &[]);
    assert!(iter.next().is_none());

If two matched elements are directly adjacent, an empty slice will be present between them:

    let slice = [10, 6, 33, 20];
    let mut iter = slice.split(|num| num % 3 == 0);

    assert_eq!(iter.next().unwrap(), &[10]);
    assert_eq!(iter.next().unwrap(), &[]);
    assert_eq!(iter.next().unwrap(), &[20]);
    assert!(iter.next().is_none());

1.0.0 · Source

#### pub fn split_mut<F>(&mut self, pred: F) -> SplitMut<'_, T, F> ⓘ
where F: FnMut(&T) -> bool,

Returns an iterator over mutable subslices separated by elements that match `pred`. The matched element is not contained in the subslices.

##### §Examples

    let mut v = [10, 40, 30, 20, 60, 50];

    for group in v.split_mut(|num| *num % 3 == 0) {
        group[0] = 1;
    }
    assert_eq!(v, [1, 40, 30, 1, 60, 1]);

1.51.0 · Source

#### pub fn split_inclusive<F>(&self, pred: F) -> SplitInclusive<'_, T, F> ⓘ
where F: FnMut(&T) -> bool,

Returns an iterator over subslices separated by elements that match `pred`. The matched element is contained in the end of the previous subslice as a terminator.

##### §Examples

    let slice = [10, 40, 33, 20];
    let mut iter = slice.split_inclusive(|num| num % 3 == 0);

    assert_eq!(iter.next().unwrap(), &[10, 40, 33]);
    assert_eq!(iter.next().unwrap(), &[20]);
    assert!(iter.next().is_none());

If the last element of the slice is matched, that element will be considered the terminator of the preceding slice. That slice will be the last item returned by the iterator.

    let slice = [3, 10, 40, 33];
    let mut iter = slice.split_inclusive(|num| num % 3 == 0);

    assert_eq!(iter.next().unwrap(), &[3]);
    assert_eq!(iter.next().unwrap(), &[10, 40, 33]);
    assert!(iter.next().is_none());

1.51.0 · Source

#### pub fn split_inclusive_mut<F>(&mut self, pred: F) -> SplitInclusiveMut<'_, T, F> ⓘ
where F: FnMut(&T) -> bool,

Returns an iterator over mutable subslices separated by elements that match `pred`. The matched element is contained in the previous subslice as a terminator.

##### §Examples

    let mut v = [10, 40, 30, 20, 60, 50];

    for group in v.split_inclusive_mut(|num| *num % 3 == 0) {
        let terminator_idx = group.len()-1;
        group[terminator_idx] = 1;
    }
    assert_eq!(v, [10, 40, 1, 20, 1, 1]);

1.27.0 · Source

#### pub fn rsplit<F>(&self, pred: F) -> RSplit<'_, T, F> ⓘ
where F: FnMut(&T) -> bool,

Returns an iterator over subslices separated by elements that match `pred`, starting at the end of the slice and working backwards. The matched element is not contained in the subslices.

##### §Examples

    let slice = [11, 22, 33, 0, 44, 55];
    let mut iter = slice.rsplit(|num| *num == 0);

    assert_eq!(iter.next().unwrap(), &[44, 55]);
    assert_eq!(iter.next().unwrap(), &[11, 22, 33]);
    assert_eq!(iter.next(), None);

As with `split()`, if the first or last element is matched, an empty slice will be the first (or last) item returned by the iterator.

    let v = &[0, 1, 1, 2, 3, 5, 8];
    let mut it = v.rsplit(|n| *n % 2 == 0);
    assert_eq!(it.next().unwrap(), &[]);
    assert_eq!(it.next().unwrap(), &[3, 5]);
    assert_eq!(it.next().unwrap(), &[1, 1]);
    assert_eq!(it.next().unwrap(), &[]);
    assert_eq!(it.next(), None);

1.27.0 · Source

#### pub fn rsplit_mut<F>(&mut self, pred: F) -> RSplitMut<'_, T, F> ⓘ
where F: FnMut(&T) -> bool,

Returns an iterator over mutable subslices separated by elements that match `pred`, starting at the end of the slice and working backwards. The matched element is not contained in the subslices.

##### §Examples

    let mut v = [100, 400, 300, 200, 600, 500];

    let mut count = 0;
    for group in v.rsplit_mut(|num| *num % 3 == 0) {
        count += 1;
        group[0] = count;
    }
    assert_eq!(v, [3, 400, 300, 2, 600, 1]);

1.0.0 · Source

#### pub fn splitn<F>(&self, n: usize, pred: F) -> SplitN<'_, T, F> ⓘ
where F: FnMut(&T) -> bool,

Returns an iterator over subslices separated by elements that match `pred`, limited to returning at most `n` items. The matched element is not contained in the subslices.

The last element returned, if any, will contain the remainder of the slice.

##### §Examples

Print the slice split once by numbers divisible by 3 (i.e., `[10, 40]`, `[20, 60, 50]`):

    let v = [10, 40, 30, 20, 60, 50];

    for group in v.splitn(2, |num| *num % 3 == 0) {
        println!("{group:?}");
    }

1.0.0 · Source

#### pub fn splitn_mut<F>(&mut self, n: usize, pred: F) -> SplitNMut<'_, T, F> ⓘ
where F: FnMut(&T) -> bool,

Returns an iterator over mutable subslices separated by elements that match `pred`, limited to returning at most `n` items. The matched element is not contained in the subslices.

The last element returned, if any, will contain the remainder of the slice.

##### §Examples

    let mut v = [10, 40, 30, 20, 60, 50];

    for group in v.splitn_mut(2, |num| *num % 3 == 0) {
        group[0] = 1;
    }
    assert_eq!(v, [1, 40, 30, 1, 60, 50]);

1.0.0 · Source

#### pub fn rsplitn<F>(&self, n: usize, pred: F) -> RSplitN<'_, T, F> ⓘ
where F: FnMut(&T) -> bool,

Returns an iterator over subslices separated by elements that match `pred` limited to returning at most `n` items. This starts at the end of the slice and works backwards. The matched element is not contained in the subslices.

The last element returned, if any, will contain the remainder of the slice.

##### §Examples

Print the slice split once, starting from the end, by numbers divisible by 3 (i.e., `[50]`, `[10, 40, 30, 20]`):

    let v = [10, 40, 30, 20, 60, 50];

    for group in v.rsplitn(2, |num| *num % 3 == 0) {
        println!("{group:?}");
    }

1.0.0 · Source

#### pub fn rsplitn_mut<F>(&mut self, n: usize, pred: F) -> RSplitNMut<'_, T, F> ⓘ
where F: FnMut(&T) -> bool,

Returns an iterator over subslices separated by elements that match `pred` limited to returning at most `n` items. This starts at the end of the slice and works backwards. The matched element is not contained in the subslices.

The last element returned, if any, will contain the remainder of the slice.

##### §Examples

    let mut s = [10, 40, 30, 20, 60, 50];

    for group in s.rsplitn_mut(2, |num| *num % 3 == 0) {
        group[0] = 1;
    }
    assert_eq!(s, [1, 40, 30, 20, 60, 1]);

Source

#### pub fn split_once<F>(&self, pred: F) -> Option<(&[T], &[T])>
where F: FnMut(&T) -> bool,

🔬This is a nightly-only experimental API. (`slice_split_once` #112811)

Splits the slice on the first element that matches the specified predicate.

If any matching elements are present in the slice, returns the prefix before the match and suffix after. The matching element itself is not included. If no elements match, returns `None`.

##### §Examples

    #![feature(slice_split_once)]
    let s = [1, 2, 3, 2, 4];
    assert_eq!(s.split_once(|&x| x == 2), Some((
        &[1][..],
        &[3, 2, 4][..]
    )));
    assert_eq!(s.split_once(|&x| x == 0), None);

Source

#### pub fn rsplit_once<F>(&self, pred: F) -> Option<(&[T], &[T])>
where F: FnMut(&T) -> bool,

🔬This is a nightly-only experimental API. (`slice_split_once` #112811)

Splits the slice on the last element that matches the specified predicate.

If any matching elements are present in the slice, returns the prefix before the match and suffix after. The matching element itself is not included. If no elements match, returns `None`.

##### §Examples

    #![feature(slice_split_once)]
    let s = [1, 2, 3, 2, 4];
    assert_eq!(s.rsplit_once(|&x| x == 2), Some((
        &[1, 2, 3][..],
        &[4][..]
    )));
    assert_eq!(s.rsplit_once(|&x| x == 0), None);

1.0.0 · Source

#### pub fn contains(&self, x: &T) -> bool
where T: PartialEq,

Returns `true` if the slice contains an element with the given value.

This operation is O(n).

Note that if you have a sorted slice, `binary_search` may be faster.

##### §Examples

    let v = [10, 40, 30];
    assert!(v.contains(&30));
    assert!(!v.contains(&50));

If you do not have a `&T`, but some other value that you can compare with one (for example, `String` implements `PartialEq<str>`), you can use `iter().any`:

    let v = [String::from("hello"), String::from("world")]; // slice of `String`
    assert!(v.iter().any(|e| e == "hello")); // search with `&str`
    assert!(!v.iter().any(|e| e == "hi"));

1.0.0 · Source

#### pub fn starts_with(&self, needle: &[T]) -> bool
where T: PartialEq,

Returns `true` if `needle` is a prefix of the slice or equal to the slice.

##### §Examples

    let v = [10, 40, 30];
    assert!(v.starts_with(&[10]));
    assert!(v.starts_with(&[10, 40]));
    assert!(v.starts_with(&v));
    assert!(!v.starts_with(&[50]));
    assert!(!v.starts_with(&[10, 50]));

Always returns `true` if `needle` is an empty slice:

    let v = &[10, 40, 30];
    assert!(v.starts_with(&[]));
    let v: &[u8] = &[];
    assert!(v.starts_with(&[]));

1.0.0 · Source

#### pub fn ends_with(&self, needle: &[T]) -> bool
where T: PartialEq,

Returns `true` if `needle` is a suffix of the slice or equal to the slice.

##### §Examples

    let v = [10, 40, 30];
    assert!(v.ends_with(&[30]));
    assert!(v.ends_with(&[40, 30]));
    assert!(v.ends_with(&v));
    assert!(!v.ends_with(&[50]));
    assert!(!v.ends_with(&[50, 30]));

Always returns `true` if `needle` is an empty slice:

    let v = &[10, 40, 30];
    assert!(v.ends_with(&[]));
    let v: &[u8] = &[];
    assert!(v.ends_with(&[]));

1.51.0 · Source

#### pub fn strip_prefix<P: SlicePattern<Item = T> + ?Sized>( &self, prefix: &P, ) -> Option<&[T]>
where T: PartialEq,

Returns a subslice with the prefix removed.

If the slice starts with `prefix`, returns the subslice after the prefix, wrapped in `Some`. If `prefix` is empty, simply returns the original slice. If `prefix` is equal to the original slice, returns an empty slice.

If the slice does not start with `prefix`, returns `None`.

##### §Examples

    let v = &[10, 40, 30];
    assert_eq!(v.strip_prefix(&[10]), Some(&[40, 30][..]));
    assert_eq!(v.strip_prefix(&[10, 40]), Some(&[30][..]));
    assert_eq!(v.strip_prefix(&[10, 40, 30]), Some(&[][..]));
    assert_eq!(v.strip_prefix(&[50]), None);
    assert_eq!(v.strip_prefix(&[10, 50]), None);

    let prefix : &str = "he";
    assert_eq!(b"hello".strip_prefix(prefix.as_bytes()),
               Some(b"llo".as_ref()));

1.51.0 · Source

#### pub fn strip_suffix<P: SlicePattern<Item = T> + ?Sized>( &self, suffix: &P, ) -> Option<&[T]>
where T: PartialEq,

Returns a subslice with the suffix removed.

If the slice ends with `suffix`, returns the subslice before the suffix, wrapped in `Some`. If `suffix` is empty, simply returns the original slice. If `suffix` is equal to the original slice, returns an empty slice.

If the slice does not end with `suffix`, returns `None`.

##### §Examples

    let v = &[10, 40, 30];
    assert_eq!(v.strip_suffix(&[30]), Some(&[10, 40][..]));
    assert_eq!(v.strip_suffix(&[40, 30]), Some(&[10][..]));
    assert_eq!(v.strip_suffix(&[10, 40, 30]), Some(&[][..]));
    assert_eq!(v.strip_suffix(&[50]), None);
    assert_eq!(v.strip_suffix(&[50, 30]), None);

1.0.0 · Source

#### pub fn binary_search(&self, x: &T) -> Result<usize, usize>
where T: Ord,

Binary searches this slice for a given element. If the slice is not sorted, the returned result is unspecified and meaningless.

If the value is found then `Result::Ok` is returned, containing the index of the matching element. If there are multiple matches, then any one of the matches could be returned. The index is chosen deterministically, but is subject to change in future versions of Rust. If the value is not found then `Result::Err` is returned, containing the index where a matching element could be inserted while maintaining sorted order.

See also `binary_search_by`, `binary_search_by_key`, and `partition_point`.

##### §Examples

Looks up a series of four elements. The first is found, with a uniquely determined position; the second and third are not found; the fourth could match any position in `[1, 4]`.

    let s = [0, 1, 1, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55];

    assert_eq!(s.binary_search(&13),  Ok(9));
    assert_eq!(s.binary_search(&4),   Err(7));
    assert_eq!(s.binary_search(&100), Err(13));
    let r = s.binary_search(&1);
    assert!(match r { Ok(1..=4) => true, _ => false, });

If you want to find that whole range of matching items, rather than an arbitrary matching one, that can be done using `partition_point`:

    let s = [0, 1, 1, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55];

    let low = s.partition_point(|x| x < &1);
    assert_eq!(low, 1);
    let high = s.partition_point(|x| x <= &1);
    assert_eq!(high, 5);
    let r = s.binary_search(&1);
    assert!((low..high).contains(&r.unwrap()));

    assert!(s[..low].iter().all(|&x| x < 1));
    assert!(s[low..high].iter().all(|&x| x == 1));
    assert!(s[high..].iter().all(|&x| x > 1));

    // For something not found, the "range" of equal items is empty
    assert_eq!(s.partition_point(|x| x < &11), 9);
    assert_eq!(s.partition_point(|x| x <= &11), 9);
    assert_eq!(s.binary_search(&11), Err(9));

If you want to insert an item to a sorted vector, while maintaining sort order, consider using `partition_point`:

    let mut s = vec![0, 1, 1, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55];
    let num = 42;
    let idx = s.partition_point(|&x| x <= num);
    // If `num` is unique, `s.partition_point(|&x| x < num)` (with `<`) is equivalent to
    // `s.binary_search(&num).unwrap_or_else(|x| x)`, but using `<=` will allow `insert`
    // to shift less elements.
    s.insert(idx, num);
    assert_eq!(s, [0, 1, 1, 1, 1, 2, 3, 5, 8, 13, 21, 34, 42, 55]);

1.0.0 · Source

#### pub fn binary_search_by<'a, F>(&'a self, f: F) -> Result<usize, usize>
where F: FnMut(&'a T) -> Ordering,

Binary searches this slice with a comparator function.

The comparator function should return an order code that indicates whether its argument is `Less`, `Equal` or `Greater` the desired target. If the slice is not sorted or if the comparator function does not implement an order consistent with the sort order of the underlying slice, the returned result is unspecified and meaningless.

If the value is found then `Result::Ok` is returned, containing the index of the matching element. If there are multiple matches, then any one of the matches could be returned. The index is chosen deterministically, but is subject to change in future versions of Rust. If the value is not found then `Result::Err` is returned, containing the index where a matching element could be inserted while maintaining sorted order.

See also `binary_search`, `binary_search_by_key`, and `partition_point`.

##### §Examples

Looks up a series of four elements. The first is found, with a uniquely determined position; the second and third are not found; the fourth could match any position in `[1, 4]`.

    let s = [0, 1, 1, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55];

    let seek = 13;
    assert_eq!(s.binary_search_by(|probe| probe.cmp(&seek)), Ok(9));
    let seek = 4;
    assert_eq!(s.binary_search_by(|probe| probe.cmp(&seek)), Err(7));
    let seek = 100;
    assert_eq!(s.binary_search_by(|probe| probe.cmp(&seek)), Err(13));
    let seek = 1;
    let r = s.binary_search_by(|probe| probe.cmp(&seek));
    assert!(match r { Ok(1..=4) => true, _ => false, });

1.10.0 · Source

#### pub fn binary_search_by_key<'a, B, F>( &'a self, b: &B, f: F, ) -> Result<usize, usize>
where F: FnMut(&'a T) -> B, B: Ord,

Binary searches this slice with a key extraction function.

Assumes that the slice is sorted by the key, for instance with `sort_by_key` using the same key extraction function. If the slice is not sorted by the key, the returned result is unspecified and meaningless.

If the value is found then `Result::Ok` is returned, containing the index of the matching element. If there are multiple matches, then any one of the matches could be returned. The index is chosen deterministically, but is subject to change in future versions of Rust. If the value is not found then `Result::Err` is returned, containing the index where a matching element could be inserted while maintaining sorted order.

See also `binary_search`, `binary_search_by`, and `partition_point`.

##### §Examples

Looks up a series of four elements in a slice of pairs sorted by their second elements. The first is found, with a uniquely determined position; the second and third are not found; the fourth could match any position in `[1, 4]`.

    let s = [(0, 0), (2, 1), (4, 1), (5, 1), (3, 1),
             (1, 2), (2, 3), (4, 5), (5, 8), (3, 13),
             (1, 21), (2, 34), (4, 55)];

    assert_eq!(s.binary_search_by_key(&13, |&(a, b)| b),  Ok(9));
    assert_eq!(s.binary_search_by_key(&4, |&(a, b)| b),   Err(7));
    assert_eq!(s.binary_search_by_key(&100, |&(a, b)| b), Err(13));
    let r = s.binary_search_by_key(&1, |&(a, b)| b);
    assert!(match r { Ok(1..=4) => true, _ => false, });

1.20.0 · Source

#### pub fn sort_unstable(&mut self)
where T: Ord,

Sorts the slice without preserving the initial order of equal elements.

This sort is unstable (i.e., may reorder equal elements), in-place (i.e., does not allocate), and O(n * log(n)) worst-case.

If the implementation of `Ord` for `T` does not implement a total order, the function may panic; even if the function exits normally, the resulting order of elements in the slice is unspecified. See also the note on panicking below.

For example `|a, b| (a - b).cmp(a)` is a comparison function that is neither transitive nor reflexive nor total, `a < b < c < a` with `a = 1, b = 2, c = 3`. For more information and examples see the `Ord` documentation.

All original elements will remain in the slice and any possible modifications via interior mutability are observed in the input. Same is true if the implementation of `Ord` for `T` panics.

Sorting types that only implement `PartialOrd` such as `f32` and `f64` require additional precautions. For example, `f32::NAN != f32::NAN`, which doesn’t fulfill the reflexivity requirement of `Ord`. By using an alternative comparison function with `slice::sort_unstable_by` such as `f32::total_cmp` or `f64::total_cmp` that defines a total order users can sort slices containing floating-point values. Alternatively, if all values in the slice are guaranteed to be in a subset for which `PartialOrd::partial_cmp` forms a total order, it’s possible to sort the slice with `sort_unstable_by(|a, b| a.partial_cmp(b).unwrap())`.

##### §Current implementation

The current implementation is based on ipnsort by Lukas Bergdoll and Orson Peters, which combines the fast average case of quicksort with the fast worst case of heapsort, achieving linear time on fully sorted and reversed inputs. On inputs with k distinct elements, the expected time to sort the data is O(n * log(k)).

It is typically faster than stable sorting, except in a few special cases, e.g., when the slice is partially sorted.

##### §Panics

May panic if the implementation of `Ord` for `T` does not implement a total order, or if the `Ord` implementation panics.

##### §Examples

    let mut v = [4, -5, 1, -3, 2];

    v.sort_unstable();
    assert_eq!(v, [-5, -3, 1, 2, 4]);

1.20.0 · Source

#### pub fn sort_unstable_by<F>(&mut self, compare: F)
where F: FnMut(&T, &T) -> Ordering,

Sorts the slice with a comparison function, without preserving the initial order of equal elements.

This sort is unstable (i.e., may reorder equal elements), in-place (i.e., does not allocate), and O(n * log(n)) worst-case.

If the comparison function `compare` does not implement a total order, the function may panic; even if the function exits normally, the resulting order of elements in the slice is unspecified. See also the note on panicking below.

For example `|a, b| (a - b).cmp(a)` is a comparison function that is neither transitive nor reflexive nor total, `a < b < c < a` with `a = 1, b = 2, c = 3`. For more information and examples see the `Ord` documentation.

All original elements will remain in the slice and any possible modifications via interior mutability are observed in the input. Same is true if `compare` panics.

##### §Current implementation

The current implementation is based on ipnsort by Lukas Bergdoll and Orson Peters, which combines the fast average case of quicksort with the fast worst case of heapsort, achieving linear time on fully sorted and reversed inputs. On inputs with k distinct elements, the expected time to sort the data is O(n * log(k)).

It is typically faster than stable sorting, except in a few special cases, e.g., when the slice is partially sorted.

##### §Panics

May panic if the `compare` does not implement a total order, or if the `compare` itself panics.

##### §Examples

    let mut v = [4, -5, 1, -3, 2];
    v.sort_unstable_by(|a, b| a.cmp(b));
    assert_eq!(v, [-5, -3, 1, 2, 4]);

    // reverse sorting
    v.sort_unstable_by(|a, b| b.cmp(a));
    assert_eq!(v, [4, 2, 1, -3, -5]);

1.20.0 · Source

#### pub fn sort_unstable_by_key<K, F>(&mut self, f: F)
where F: FnMut(&T) -> K, K: Ord,

Sorts the slice with a key extraction function, without preserving the initial order of equal elements.

This sort is unstable (i.e., may reorder equal elements), in-place (i.e., does not allocate), and O(n * log(n)) worst-case.

If the implementation of `Ord` for `K` does not implement a total order, the function may panic; even if the function exits normally, the resulting order of elements in the slice is unspecified. See also the note on panicking below.

For example `|a, b| (a - b).cmp(a)` is a comparison function that is neither transitive nor reflexive nor total, `a < b < c < a` with `a = 1, b = 2, c = 3`. For more information and examples see the `Ord` documentation.

All original elements will remain in the slice and any possible modifications via interior mutability are observed in the input. Same is true if the implementation of `Ord` for `K` panics.

##### §Current implementation

The current implementation is based on ipnsort by Lukas Bergdoll and Orson Peters, which combines the fast average case of quicksort with the fast worst case of heapsort, achieving linear time on fully sorted and reversed inputs. On inputs with k distinct elements, the expected time to sort the data is O(n * log(k)).

It is typically faster than stable sorting, except in a few special cases, e.g., when the slice is partially sorted.

##### §Panics

May panic if the implementation of `Ord` for `K` does not implement a total order, or if the `Ord` implementation panics.

##### §Examples

    let mut v = [4i32, -5, 1, -3, 2];

    v.sort_unstable_by_key(|k| k.abs());
    assert_eq!(v, [1, 2, -3, 4, -5]);

1.49.0 · Source

#### pub fn select_nth_unstable( &mut self, index: usize, ) -> (&mut [T], &mut T, &mut [T])
where T: Ord,

Reorders the slice such that the element at `index` is at a sort-order position. All elements before `index` will be `<=` to this value, and all elements after will be `>=` to it.

This reordering is unstable (i.e. any element that compares equal to the nth element may end up at that position), in-place (i.e. does not allocate), and runs in O(n) time. This function is also known as “kth element” in other libraries.

Returns a triple that partitions the reordered slice:

- The unsorted subslice before `index`, whose elements all satisfy `x <= self[index]`.

- The element at `index`.

- The unsorted subslice after `index`, whose elements all satisfy `x >= self[index]`.

##### §Current implementation

The current algorithm is an introselect implementation based on ipnsort by Lukas Bergdoll and Orson Peters, which is also the basis for `sort_unstable`. The fallback algorithm is Median of Medians using Tukey’s Ninther for pivot selection, which guarantees linear runtime for all inputs.

##### §Panics

Panics when `index >= len()`, and so always panics on empty slices.

May panic if the implementation of `Ord` for `T` does not implement a total order.

##### §Examples

    let mut v = [-5i32, 4, 2, -3, 1];

    // Find the items `<=` to the median, the median itself, and the items `>=` to it.
    let (lesser, median, greater) = v.select_nth_unstable(2);

    assert!(lesser == [-3, -5] || lesser == [-5, -3]);
    assert_eq!(median, &mut 1);
    assert!(greater == [4, 2] || greater == [2, 4]);

    // We are only guaranteed the slice will be one of the following, based on the way we sort
    // about the specified index.
    assert!(v == [-3, -5, 1, 2, 4] ||
            v == [-5, -3, 1, 2, 4] ||
            v == [-3, -5, 1, 4, 2] ||
            v == [-5, -3, 1, 4, 2]);

1.49.0 · Source

#### pub fn select_nth_unstable_by<F>( &mut self, index: usize, compare: F, ) -> (&mut [T], &mut T, &mut [T])
where F: FnMut(&T, &T) -> Ordering,

Reorders the slice with a comparator function such that the element at `index` is at a sort-order position. All elements before `index` will be `<=` to this value, and all elements after will be `>=` to it, according to the comparator function.

This reordering is unstable (i.e. any element that compares equal to the nth element may end up at that position), in-place (i.e. does not allocate), and runs in O(n) time. This function is also known as “kth element” in other libraries.

Returns a triple partitioning the reordered slice:

- The unsorted subslice before `index`, whose elements all satisfy `compare(x, self[index]).is_le()`.

- The element at `index`.

- The unsorted subslice after `index`, whose elements all satisfy `compare(x, self[index]).is_ge()`.

##### §Current implementation

The current algorithm is an introselect implementation based on ipnsort by Lukas Bergdoll and Orson Peters, which is also the basis for `sort_unstable`. The fallback algorithm is Median of Medians using Tukey’s Ninther for pivot selection, which guarantees linear runtime for all inputs.

##### §Panics

Panics when `index >= len()`, and so always panics on empty slices.

May panic if `compare` does not implement a total order.

##### §Examples

    let mut v = [-5i32, 4, 2, -3, 1];

    // Find the items `>=` to the median, the median itself, and the items `<=` to it, by using
    // a reversed comparator.
    let (before, median, after) = v.select_nth_unstable_by(2, |a, b| b.cmp(a));

    assert!(before == [4, 2] || before == [2, 4]);
    assert_eq!(median, &mut 1);
    assert!(after == [-3, -5] || after == [-5, -3]);

    // We are only guaranteed the slice will be one of the following, based on the way we sort
    // about the specified index.
    assert!(v == [2, 4, 1, -5, -3] ||
            v == [2, 4, 1, -3, -5] ||
            v == [4, 2, 1, -5, -3] ||
            v == [4, 2, 1, -3, -5]);

1.49.0 · Source

#### pub fn select_nth_unstable_by_key<K, F>( &mut self, index: usize, f: F, ) -> (&mut [T], &mut T, &mut [T])
where F: FnMut(&T) -> K, K: Ord,

Reorders the slice with a key extraction function such that the element at `index` is at a sort-order position. All elements before `index` will have keys `<=` to the key at `index`, and all elements after will have keys `>=` to it.

This reordering is unstable (i.e. any element that compares equal to the nth element may end up at that position), in-place (i.e. does not allocate), and runs in O(n) time. This function is also known as “kth element” in other libraries.

Returns a triple partitioning the reordered slice:

- The unsorted subslice before `index`, whose elements all satisfy `f(x) <= f(self[index])`.

- The element at `index`.

- The unsorted subslice after `index`, whose elements all satisfy `f(x) >= f(self[index])`.

##### §Current implementation

The current algorithm is an introselect implementation based on ipnsort by Lukas Bergdoll and Orson Peters, which is also the basis for `sort_unstable`. The fallback algorithm is Median of Medians using Tukey’s Ninther for pivot selection, which guarantees linear runtime for all inputs.

##### §Panics

Panics when `index >= len()`, meaning it always panics on empty slices.

May panic if `K: Ord` does not implement a total order.

##### §Examples

    let mut v = [-5i32, 4, 1, -3, 2];

    // Find the items `<=` to the absolute median, the absolute median itself, and the items
    // `>=` to it.
    let (lesser, median, greater) = v.select_nth_unstable_by_key(2, |a| a.abs());

    assert!(lesser == [1, 2] || lesser == [2, 1]);
    assert_eq!(median, &mut -3);
    assert!(greater == [4, -5] || greater == [-5, 4]);

    // We are only guaranteed the slice will be one of the following, based on the way we sort
    // about the specified index.
    assert!(v == [1, 2, -3, 4, -5] ||
            v == [1, 2, -3, -5, 4] ||
            v == [2, 1, -3, 4, -5] ||
            v == [2, 1, -3, -5, 4]);

Source

#### pub fn partition_dedup(&mut self) -> (&mut [T], &mut [T])
where T: PartialEq,

🔬This is a nightly-only experimental API. (`slice_partition_dedup` #54279)

Moves all consecutive repeated elements to the end of the slice according to the `PartialEq` trait implementation.

Returns two slices. The first contains no consecutive repeated elements. The second contains all the duplicates in no specified order.

If the slice is sorted, the first returned slice contains no duplicates.

##### §Examples

    #![feature(slice_partition_dedup)]

    let mut slice = [1, 2, 2, 3, 3, 2, 1, 1];

    let (dedup, duplicates) = slice.partition_dedup();

    assert_eq!(dedup, [1, 2, 3, 2, 1]);
    assert_eq!(duplicates, [2, 3, 1]);

Source

#### pub fn partition_dedup_by<F>(&mut self, same_bucket: F) -> (&mut [T], &mut [T])
where F: FnMut(&mut T, &mut T) -> bool,

🔬This is a nightly-only experimental API. (`slice_partition_dedup` #54279)

Moves all but the first of consecutive elements to the end of the slice satisfying a given equality relation.

Returns two slices. The first contains no consecutive repeated elements. The second contains all the duplicates in no specified order.

The `same_bucket` function is passed references to two elements from the slice and must determine if the elements compare equal. The elements are passed in opposite order from their order in the slice, so if `same_bucket(a, b)` returns `true`, `a` is moved at the end of the slice.

If the slice is sorted, the first returned slice contains no duplicates.

##### §Examples

    #![feature(slice_partition_dedup)]

    let mut slice = ["foo", "Foo", "BAZ", "Bar", "bar", "baz", "BAZ"];

    let (dedup, duplicates) = slice.partition_dedup_by(|a, b| a.eq_ignore_ascii_case(b));

    assert_eq!(dedup, ["foo", "BAZ", "Bar", "baz"]);
    assert_eq!(duplicates, ["bar", "Foo", "BAZ"]);

Source

#### pub fn partition_dedup_by_key<K, F>(&mut self, key: F) -> (&mut [T], &mut [T])
where F: FnMut(&mut T) -> K, K: PartialEq,

🔬This is a nightly-only experimental API. (`slice_partition_dedup` #54279)

Moves all but the first of consecutive elements to the end of the slice that resolve to the same key.

Returns two slices. The first contains no consecutive repeated elements. The second contains all the duplicates in no specified order.

If the slice is sorted, the first returned slice contains no duplicates.

##### §Examples

    #![feature(slice_partition_dedup)]

    let mut slice = [10, 20, 21, 30, 30, 20, 11, 13];

    let (dedup, duplicates) = slice.partition_dedup_by_key(|i| *i / 10);

    assert_eq!(dedup, [10, 20, 30, 20, 11]);
    assert_eq!(duplicates, [21, 30, 13]);

1.26.0 · Source

#### pub fn rotate_left(&mut self, mid: usize)

Rotates the slice in-place such that the first `mid` elements of the slice move to the end while the last `self.len() - mid` elements move to the front.

After calling `rotate_left`, the element previously at index `mid` will become the first element in the slice.

##### §Panics

This function will panic if `mid` is greater than the length of the slice. Note that `mid == self.len()` does not panic and is a no-op rotation.

##### §Complexity

Takes linear (in `self.len()`) time.

##### §Examples

    let mut a = ['a', 'b', 'c', 'd', 'e', 'f'];
    a.rotate_left(2);
    assert_eq!(a, ['c', 'd', 'e', 'f', 'a', 'b']);

Rotating a subslice:

    let mut a = ['a', 'b', 'c', 'd', 'e', 'f'];
    a[1..5].rotate_left(1);
    assert_eq!(a, ['a', 'c', 'd', 'e', 'b', 'f']);

1.26.0 · Source

#### pub fn rotate_right(&mut self, k: usize)

Rotates the slice in-place such that the first `self.len() - k` elements of the slice move to the end while the last `k` elements move to the front.

After calling `rotate_right`, the element previously at index `self.len() - k` will become the first element in the slice.

##### §Panics

This function will panic if `k` is greater than the length of the slice. Note that `k == self.len()` does not panic and is a no-op rotation.

##### §Complexity

Takes linear (in `self.len()`) time.

##### §Examples

    let mut a = ['a', 'b', 'c', 'd', 'e', 'f'];
    a.rotate_right(2);
    assert_eq!(a, ['e', 'f', 'a', 'b', 'c', 'd']);

Rotating a subslice:

    let mut a = ['a', 'b', 'c', 'd', 'e', 'f'];
    a[1..5].rotate_right(1);
    assert_eq!(a, ['a', 'e', 'b', 'c', 'd', 'f']);

1.50.0 · Source

#### pub fn fill(&mut self, value: T)
where T: Clone,

Fills `self` with elements by cloning `value`.

##### §Examples

    let mut buf = vec![0; 10];
    buf.fill(1);
    assert_eq!(buf, vec![1; 10]);

1.51.0 · Source

#### pub fn fill_with<F>(&mut self, f: F)
where F: FnMut() -> T,

Fills `self` with elements returned by calling a closure repeatedly.

This method uses a closure to create new values. If you’d rather `Clone` a given value, use `fill`. If you want to use the `Default` trait to generate values, you can pass `Default::default` as the argument.

##### §Examples

    let mut buf = vec![1; 10];
    buf.fill_with(Default::default);
    assert_eq!(buf, vec![0; 10]);

1.7.0 · Source

#### pub fn clone_from_slice(&mut self, src: &[T])
where T: Clone,

Copies the elements from `src` into `self`.

The length of `src` must be the same as `self`.

##### §Panics

This function will panic if the two slices have different lengths.

##### §Examples

Cloning two elements from a slice into another:

    let src = [1, 2, 3, 4];
    let mut dst = [0, 0];

    // Because the slices have to be the same length,
    // we slice the source slice from four elements
    // to two. It will panic if we don't do this.
    dst.clone_from_slice(&src[2..]);

    assert_eq!(src, [1, 2, 3, 4]);
    assert_eq!(dst, [3, 4]);

Rust enforces that there can only be one mutable reference with no immutable references to a particular piece of data in a particular scope. Because of this, attempting to use `clone_from_slice` on a single slice will result in a compile failure:

ⓘ

    let mut slice = [1, 2, 3, 4, 5];

    slice[..2].clone_from_slice(&slice[3..]); // compile fail!

To work around this, we can use `split_at_mut` to create two distinct sub-slices from a slice:

    let mut slice = [1, 2, 3, 4, 5];

    {
        let (left, right) = slice.split_at_mut(2);
        left.clone_from_slice(&right[1..]);
    }

    assert_eq!(slice, [4, 5, 3, 4, 5]);

1.9.0 (const: 1.87.0) · Source

#### pub const fn copy_from_slice(&mut self, src: &[T])
where T: Copy,

Copies all elements from `src` into `self`, using a memcpy.

The length of `src` must be the same as `self`.

If `T` does not implement `Copy`, use `clone_from_slice`.

##### §Panics

This function will panic if the two slices have different lengths.

##### §Examples

Copying two elements from a slice into another:

    let src = [1, 2, 3, 4];
    let mut dst = [0, 0];

    // Because the slices have to be the same length,
    // we slice the source slice from four elements
    // to two. It will panic if we don't do this.
    dst.copy_from_slice(&src[2..]);

    assert_eq!(src, [1, 2, 3, 4]);
    assert_eq!(dst, [3, 4]);

Rust enforces that there can only be one mutable reference with no immutable references to a particular piece of data in a particular scope. Because of this, attempting to use `copy_from_slice` on a single slice will result in a compile failure:

ⓘ

    let mut slice = [1, 2, 3, 4, 5];

    slice[..2].copy_from_slice(&slice[3..]); // compile fail!

To work around this, we can use `split_at_mut` to create two distinct sub-slices from a slice:

    let mut slice = [1, 2, 3, 4, 5];

    {
        let (left, right) = slice.split_at_mut(2);
        left.copy_from_slice(&right[1..]);
    }

    assert_eq!(slice, [4, 5, 3, 4, 5]);

1.37.0 · Source

#### pub fn copy_within<R: RangeBounds<usize>>(&mut self, src: R, dest: usize)
where T: Copy,

Copies elements from one part of the slice to another part of itself, using a memmove.

`src` is the range within `self` to copy from. `dest` is the starting index of the range within `self` to copy to, which will have the same length as `src`. The two ranges may overlap. The ends of the two ranges must be less than or equal to `self.len()`.

##### §Panics

This function will panic if either range exceeds the end of the slice, or if the end of `src` is before the start.

##### §Examples

Copying four bytes within a slice:

    let mut bytes = *b"Hello, World!";

    bytes.copy_within(1..5, 8);

    assert_eq!(&bytes, b"Hello, Wello!");

1.27.0 · Source

#### pub fn swap_with_slice(&mut self, other: &mut [T])

Swaps all elements in `self` with those in `other`.

The length of `other` must be the same as `self`.

##### §Panics

This function will panic if the two slices have different lengths.

##### §Example

Swapping two elements across slices:

    let mut slice1 = [0, 0];
    let mut slice2 = [1, 2, 3, 4];

    slice1.swap_with_slice(&mut slice2[2..]);

    assert_eq!(slice1, [3, 4]);
    assert_eq!(slice2, [1, 2, 0, 0]);

Rust enforces that there can only be one mutable reference to a particular piece of data in a particular scope. Because of this, attempting to use `swap_with_slice` on a single slice will result in a compile failure:

ⓘ

    let mut slice = [1, 2, 3, 4, 5];
    slice[..2].swap_with_slice(&mut slice[3..]); // compile fail!

To work around this, we can use `split_at_mut` to create two distinct mutable sub-slices from a slice:

    let mut slice = [1, 2, 3, 4, 5];

    {
        let (left, right) = slice.split_at_mut(2);
        left.swap_with_slice(&mut right[1..]);
    }

    assert_eq!(slice, [4, 5, 3, 1, 2]);

1.30.0 · Source

#### pub unsafe fn align_to<U>(&self) -> (&[T], &[U], &[T])

Transmutes the slice to a slice of another type, ensuring alignment of the types is maintained.

This method splits the slice into three distinct slices: prefix, correctly aligned middle slice of a new type, and the suffix slice. The middle part will be as big as possible under the given alignment constraint and element size.

This method has no purpose when either input element `T` or output element `U` are zero-sized and will return the original slice without splitting anything.

##### §Safety

This method is essentially a `transmute` with respect to the elements in the returned middle slice, so all the usual caveats pertaining to `transmute::<T, U>` also apply here.

##### §Examples

Basic usage:

    unsafe {
        let bytes: [u8; 7] = [1, 2, 3, 4, 5, 6, 7];
        let (prefix, shorts, suffix) = bytes.align_to::<u16>();
        // less_efficient_algorithm_for_bytes(prefix);
        // more_efficient_algorithm_for_aligned_shorts(shorts);
        // less_efficient_algorithm_for_bytes(suffix);
    }

1.30.0 · Source

#### pub unsafe fn align_to_mut<U>(&mut self) -> (&mut [T], &mut [U], &mut [T])

Transmutes the mutable slice to a mutable slice of another type, ensuring alignment of the types is maintained.

This method splits the slice into three distinct slices: prefix, correctly aligned middle slice of a new type, and the suffix slice. The middle part will be as big as possible under the given alignment constraint and element size.

This method has no purpose when either input element `T` or output element `U` are zero-sized and will return the original slice without splitting anything.

##### §Safety

This method is essentially a `transmute` with respect to the elements in the returned middle slice, so all the usual caveats pertaining to `transmute::<T, U>` also apply here.

##### §Examples

Basic usage:

    unsafe {
        let mut bytes: [u8; 7] = [1, 2, 3, 4, 5, 6, 7];
        let (prefix, shorts, suffix) = bytes.align_to_mut::<u16>();
        // less_efficient_algorithm_for_bytes(prefix);
        // more_efficient_algorithm_for_aligned_shorts(shorts);
        // less_efficient_algorithm_for_bytes(suffix);
    }

Source

#### pub fn as_simd<const LANES: usize>(&self) -> (&[T], &[Simd<T, LANES>], &[T])
where Simd<T, LANES>: AsRef<[T; LANES]>, T: SimdElement, LaneCount<LANES>: SupportedLaneCount,

🔬This is a nightly-only experimental API. (`portable_simd` #86656)

Splits a slice into a prefix, a middle of aligned SIMD types, and a suffix.

This is a safe wrapper around `slice::align_to`, so inherits the same guarantees as that method.

##### §Panics

This will panic if the size of the SIMD type is different from `LANES` times that of the scalar.

At the time of writing, the trait restrictions on `Simd<T, LANES>` keeps that from ever happening, as only power-of-two numbers of lanes are supported. It’s possible that, in the future, those restrictions might be lifted in a way that would make it possible to see panics from this method for something like `LANES == 3`.

##### §Examples

    #![feature(portable_simd)]
    use core::simd::prelude::*;

    let short = &[1, 2, 3];
    let (prefix, middle, suffix) = short.as_simd::<4>();
    assert_eq!(middle, []); // Not enough elements for anything in the middle

    // They might be split in any possible way between prefix and suffix
    let it = prefix.iter().chain(suffix).copied();
    assert_eq!(it.collect::<Vec<_>>(), vec![1, 2, 3]);

    fn basic_simd_sum(x: &[f32]) -> f32 {
        use std::ops::Add;
        let (prefix, middle, suffix) = x.as_simd();
        let sums = f32x4::from_array([
            prefix.iter().copied().sum(),
            0.0,
            0.0,
            suffix.iter().copied().sum(),
        ]);
        let sums = middle.iter().copied().fold(sums, f32x4::add);
        sums.reduce_sum()
    }

    let numbers: Vec<f32> = (1..101).map(|x| x as _).collect();
    assert_eq!(basic_simd_sum(&numbers[1..99]), 4949.0);

Source

#### pub fn as_simd_mut<const LANES: usize>( &mut self, ) -> (&mut [T], &mut [Simd<T, LANES>], &mut [T])
where Simd<T, LANES>: AsMut<[T; LANES]>, T: SimdElement, LaneCount<LANES>: SupportedLaneCount,

🔬This is a nightly-only experimental API. (`portable_simd` #86656)

Splits a mutable slice into a mutable prefix, a middle of aligned SIMD types, and a mutable suffix.

This is a safe wrapper around `slice::align_to_mut`, so inherits the same guarantees as that method.

This is the mutable version of `slice::as_simd`; see that for examples.

##### §Panics

This will panic if the size of the SIMD type is different from `LANES` times that of the scalar.

At the time of writing, the trait restrictions on `Simd<T, LANES>` keeps that from ever happening, as only power-of-two numbers of lanes are supported. It’s possible that, in the future, those restrictions might be lifted in a way that would make it possible to see panics from this method for something like `LANES == 3`.

1.82.0 · Source

#### pub fn is_sorted(&self) -> bool
where T: PartialOrd,

Checks if the elements of this slice are sorted.

That is, for each element `a` and its following element `b`, `a <= b` must hold. If the slice yields exactly zero or one element, `true` is returned.

Note that if `Self::Item` is only `PartialOrd`, but not `Ord`, the above definition implies that this function returns `false` if any two consecutive items are not comparable.

##### §Examples

    let empty: [i32; 0] = [];

    assert!([1, 2, 2, 9].is_sorted());
    assert!(![1, 3, 2, 4].is_sorted());
    assert!([0].is_sorted());
    assert!(empty.is_sorted());
    assert!(![0.0, 1.0, f32::NAN].is_sorted());

1.82.0 · Source

#### pub fn is_sorted_by<'a, F>(&'a self, compare: F) -> bool
where F: FnMut(&'a T, &'a T) -> bool,

Checks if the elements of this slice are sorted using the given comparator function.

Instead of using `PartialOrd::partial_cmp`, this function uses the given `compare` function to determine whether two elements are to be considered in sorted order.

##### §Examples

    assert!([1, 2, 2, 9].is_sorted_by(|a, b| a <= b));
    assert!(![1, 2, 2, 9].is_sorted_by(|a, b| a < b));

    assert!([0].is_sorted_by(|a, b| true));
    assert!([0].is_sorted_by(|a, b| false));

    let empty: [i32; 0] = [];
    assert!(empty.is_sorted_by(|a, b| false));
    assert!(empty.is_sorted_by(|a, b| true));

1.82.0 · Source

#### pub fn is_sorted_by_key<'a, F, K>(&'a self, f: F) -> bool
where F: FnMut(&'a T) -> K, K: PartialOrd,

Checks if the elements of this slice are sorted using the given key extraction function.

Instead of comparing the slice’s elements directly, this function compares the keys of the elements, as determined by `f`. Apart from that, it’s equivalent to `is_sorted`; see its documentation for more information.

##### §Examples

    assert!(["c", "bb", "aaa"].is_sorted_by_key(|s| s.len()));
    assert!(![-2i32, -1, 0, 3].is_sorted_by_key(|n| n.abs()));

1.52.0 · Source

#### pub fn partition_point<P>(&self, pred: P) -> usize
where P: FnMut(&T) -> bool,

Returns the index of the partition point according to the given predicate (the index of the first element of the second partition).

The slice is assumed to be partitioned according to the given predicate. This means that all elements for which the predicate returns true are at the start of the slice and all elements for which the predicate returns false are at the end. For example, `[7, 15, 3, 5, 4, 12, 6]` is partitioned under the predicate `x % 2 != 0` (all odd numbers are at the start, all even at the end).

If this slice is not partitioned, the returned result is unspecified and meaningless, as this method performs a kind of binary search.

See also `binary_search`, `binary_search_by`, and `binary_search_by_key`.

##### §Examples

    let v = [1, 2, 3, 3, 5, 6, 7];
    let i = v.partition_point(|&x| x < 5);

    assert_eq!(i, 4);
    assert!(v[..i].iter().all(|&x| x < 5));
    assert!(v[i..].iter().all(|&x| !(x < 5)));

If all elements of the slice match the predicate, including if the slice is empty, then the length of the slice will be returned:

    let a = [2, 4, 8];
    assert_eq!(a.partition_point(|x| x < &100), a.len());
    let a: [i32; 0] = [];
    assert_eq!(a.partition_point(|x| x < &100), 0);

If you want to insert an item to a sorted vector, while maintaining sort order:

    let mut s = vec![0, 1, 1, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55];
    let num = 42;
    let idx = s.partition_point(|&x| x <= num);
    s.insert(idx, num);
    assert_eq!(s, [0, 1, 1, 1, 1, 2, 3, 5, 8, 13, 21, 34, 42, 55]);

1.87.0 · Source

#### pub fn split_off<'a, R: OneSidedRange<usize>>( self: &mut &'a Self, range: R, ) -> Option<&'a Self>

Removes the subslice corresponding to the given range and returns a reference to it.

Returns `None` and does not modify the slice if the given range is out of bounds.

Note that this method only accepts one-sided ranges such as `2..` or `..6`, but not `2..6`.

##### §Examples

Splitting off the first three elements of a slice:

    let mut slice: &[_] = &['a', 'b', 'c', 'd'];
    let mut first_three = slice.split_off(..3).unwrap();

    assert_eq!(slice, &['d']);
    assert_eq!(first_three, &['a', 'b', 'c']);

Splitting off the last two elements of a slice:

    let mut slice: &[_] = &['a', 'b', 'c', 'd'];
    let mut tail = slice.split_off(2..).unwrap();

    assert_eq!(slice, &['a', 'b']);
    assert_eq!(tail, &['c', 'd']);

Getting `None` when `range` is out of bounds:

    let mut slice: &[_] = &['a', 'b', 'c', 'd'];

    assert_eq!(None, slice.split_off(5..));
    assert_eq!(None, slice.split_off(..5));
    assert_eq!(None, slice.split_off(..=4));
    let expected: &[char] = &['a', 'b', 'c', 'd'];
    assert_eq!(Some(expected), slice.split_off(..4));

1.87.0 · Source

#### pub fn split_off_mut<'a, R: OneSidedRange<usize>>( self: &mut &'a mut Self, range: R, ) -> Option<&'a mut Self>

Removes the subslice corresponding to the given range and returns a mutable reference to it.

Returns `None` and does not modify the slice if the given range is out of bounds.

Note that this method only accepts one-sided ranges such as `2..` or `..6`, but not `2..6`.

##### §Examples

Splitting off the first three elements of a slice:

    let mut slice: &mut [_] = &mut ['a', 'b', 'c', 'd'];
    let mut first_three = slice.split_off_mut(..3).unwrap();

    assert_eq!(slice, &mut ['d']);
    assert_eq!(first_three, &mut ['a', 'b', 'c']);

Taking the last two elements of a slice:

    let mut slice: &mut [_] = &mut ['a', 'b', 'c', 'd'];
    let mut tail = slice.split_off_mut(2..).unwrap();

    assert_eq!(slice, &mut ['a', 'b']);
    assert_eq!(tail, &mut ['c', 'd']);

Getting `None` when `range` is out of bounds:

    let mut slice: &mut [_] = &mut ['a', 'b', 'c', 'd'];

    assert_eq!(None, slice.split_off_mut(5..));
    assert_eq!(None, slice.split_off_mut(..5));
    assert_eq!(None, slice.split_off_mut(..=4));
    let expected: &mut [_] = &mut ['a', 'b', 'c', 'd'];
    assert_eq!(Some(expected), slice.split_off_mut(..4));

1.87.0 (const: unstable) · Source

#### pub fn split_off_first<'a>(self: &mut &'a Self) -> Option<&'a T>

Removes the first element of the slice and returns a reference to it.

Returns `None` if the slice is empty.

##### §Examples

    let mut slice: &[_] = &['a', 'b', 'c'];
    let first = slice.split_off_first().unwrap();

    assert_eq!(slice, &['b', 'c']);
    assert_eq!(first, &'a');

1.87.0 (const: unstable) · Source

#### pub fn split_off_first_mut<'a>(self: &mut &'a mut Self) -> Option<&'a mut T>

Removes the first element of the slice and returns a mutable reference to it.

Returns `None` if the slice is empty.

##### §Examples

    let mut slice: &mut [_] = &mut ['a', 'b', 'c'];
    let first = slice.split_off_first_mut().unwrap();
    *first = 'd';

    assert_eq!(slice, &['b', 'c']);
    assert_eq!(first, &'d');

1.87.0 (const: unstable) · Source

#### pub fn split_off_last<'a>(self: &mut &'a Self) -> Option<&'a T>

Removes the last element of the slice and returns a reference to it.

Returns `None` if the slice is empty.

##### §Examples

    let mut slice: &[_] = &['a', 'b', 'c'];
    let last = slice.split_off_last().unwrap();

    assert_eq!(slice, &['a', 'b']);
    assert_eq!(last, &'c');

1.87.0 (const: unstable) · Source

#### pub fn split_off_last_mut<'a>(self: &mut &'a mut Self) -> Option<&'a mut T>

Removes the last element of the slice and returns a mutable reference to it.

Returns `None` if the slice is empty.

##### §Examples

    let mut slice: &mut [_] = &mut ['a', 'b', 'c'];
    let last = slice.split_off_last_mut().unwrap();
    *last = 'd';

    assert_eq!(slice, &['a', 'b']);
    assert_eq!(last, &'d');

1.86.0 · Source

#### pub unsafe fn get_disjoint_unchecked_mut<I, const N: usize>( &mut self, indices: [I; N], ) -> [&mut I::Output; N]
where I: GetDisjointMutIndex + SliceIndex<Self>,

Returns mutable references to many indices at once, without doing any checks.

An index can be either a `usize`, a `Range` or a `RangeInclusive`. Note that this method takes an array, so all indices must be of the same type. If passed an array of `usize`s this method gives back an array of mutable references to single elements, while if passed an array of ranges it gives back an array of mutable references to slices.

For a safe alternative see `get_disjoint_mut`.

##### §Safety

Calling this method with overlapping or out-of-bounds indices is undefined behavior even if the resulting references are not used.

##### §Examples

    let x = &mut [1, 2, 4];

    unsafe {
        let [a, b] = x.get_disjoint_unchecked_mut([0, 2]);
        *a *= 10;
        *b *= 100;
    }
    assert_eq!(x, &[10, 2, 400]);

    unsafe {
        let [a, b] = x.get_disjoint_unchecked_mut([0..1, 1..3]);
        a[0] = 8;
        b[0] = 88;
        b[1] = 888;
    }
    assert_eq!(x, &[8, 88, 888]);

    unsafe {
        let [a, b] = x.get_disjoint_unchecked_mut([1..=2, 0..=0]);
        a[0] = 11;
        a[1] = 111;
        b[0] = 1;
    }
    assert_eq!(x, &[1, 11, 111]);

1.86.0 · Source

#### pub fn get_disjoint_mut<I, const N: usize>( &mut self, indices: [I; N], ) -> Result<[&mut I::Output; N], GetDisjointMutError>
where I: GetDisjointMutIndex + SliceIndex<Self>,

Returns mutable references to many indices at once.

An index can be either a `usize`, a `Range` or a `RangeInclusive`. Note that this method takes an array, so all indices must be of the same type. If passed an array of `usize`s this method gives back an array of mutable references to single elements, while if passed an array of ranges it gives back an array of mutable references to slices.

Returns an error if any index is out-of-bounds, or if there are overlapping indices. An empty range is not considered to overlap if it is located at the beginning or at the end of another range, but is considered to overlap if it is located in the middle.

This method does a O(n^2) check to check that there are no overlapping indices, so be careful when passing many indices.

##### §Examples

    let v = &mut [1, 2, 3];
    if let Ok([a, b]) = v.get_disjoint_mut([0, 2]) {
        *a = 413;
        *b = 612;
    }
    assert_eq!(v, &[413, 2, 612]);

    if let Ok([a, b]) = v.get_disjoint_mut([0..1, 1..3]) {
        a[0] = 8;
        b[0] = 88;
        b[1] = 888;
    }
    assert_eq!(v, &[8, 88, 888]);

    if let Ok([a, b]) = v.get_disjoint_mut([1..=2, 0..=0]) {
        a[0] = 11;
        a[1] = 111;
        b[0] = 1;
    }
    assert_eq!(v, &[1, 11, 111]);

Source

#### pub fn element_offset(&self, element: &T) -> Option<usize>

🔬This is a nightly-only experimental API. (`substr_range` #126769)

Returns the index that an element reference points to.

Returns `None` if `element` does not point to the start of an element within the slice.

This method is useful for extending slice iterators like `slice::split`.

Note that this uses pointer arithmetic and does not compare elements. To find the index of an element via comparison, use `.iter().position()` instead.

##### §Panics

Panics if `T` is zero-sized.

##### §Examples

Basic usage:

    #![feature(substr_range)]

    let nums: &[u32] = &[1, 7, 1, 1];
    let num = &nums[2];

    assert_eq!(num, &1);
    assert_eq!(nums.element_offset(num), Some(2));

Returning `None` with an unaligned element:

    #![feature(substr_range)]

    let arr: &[[u32; 2]] = &[[0, 1], [2, 3]];
    let flat_arr: &[u32] = arr.as_flattened();

    let ok_elm: &[u32; 2] = flat_arr[0..2].try_into().unwrap();
    let weird_elm: &[u32; 2] = flat_arr[1..3].try_into().unwrap();

    assert_eq!(ok_elm, &[0, 1]);
    assert_eq!(weird_elm, &[1, 2]);

    assert_eq!(arr.element_offset(ok_elm), Some(0)); // Points to element 0
    assert_eq!(arr.element_offset(weird_elm), None); // Points between element 0 and 1

Source

#### pub fn subslice_range(&self, subslice: &[T]) -> Option<Range<usize>>

🔬This is a nightly-only experimental API. (`substr_range` #126769)

Returns the range of indices that a subslice points to.

Returns `None` if `subslice` does not point within the slice or if it is not aligned with the elements in the slice.

This method does not compare elements. Instead, this method finds the location in the slice that `subslice` was obtained from. To find the index of a subslice via comparison, instead use `.windows()``.position()`.

This method is useful for extending slice iterators like `slice::split`.

Note that this may return a false positive (either `Some(0..0)` or `Some(self.len()..self.len())`) if `subslice` has a length of zero and points to the beginning or end of another, separate, slice.

##### §Panics

Panics if `T` is zero-sized.

##### §Examples

Basic usage:

    #![feature(substr_range)]

    let nums = &[0, 5, 10, 0, 0, 5];

    let mut iter = nums
        .split(|t| *t == 0)
        .map(|n| nums.subslice_range(n).unwrap());

    assert_eq!(iter.next(), Some(0..0));
    assert_eq!(iter.next(), Some(1..3));
    assert_eq!(iter.next(), Some(4..4));
    assert_eq!(iter.next(), Some(5..6));

Source§

### impl<T> [MaybeUninit<T>]

Source

#### pub fn align_to_uninit_mut<U>( &mut self, ) -> (&mut Self, &mut [MaybeUninit<U>], &mut Self)

🔬This is a nightly-only experimental API. (`align_to_uninit_mut` #139062)

Transmutes the mutable uninitialized slice to a mutable uninitialized slice of another type, ensuring alignment of the types is maintained.

This is a safe wrapper around `slice::align_to_mut`, so inherits the same guarantees as that method.

##### §Examples

    #![feature(align_to_uninit_mut)]
    use std::mem::MaybeUninit;

    pub struct BumpAllocator<'scope> {
        memory: &'scope mut [MaybeUninit<u8>],
    }

    impl<'scope> BumpAllocator<'scope> {
        pub fn new(memory: &'scope mut [MaybeUninit<u8>]) -> Self {
            Self { memory }
        }
        pub fn try_alloc_uninit<T>(&mut self) -> Option<&'scope mut MaybeUninit<T>> {
            let first_end = self.memory.as_ptr().align_offset(align_of::<T>()) + size_of::<T>();
            let prefix = self.memory.split_off_mut(..first_end)?;
            Some(&mut prefix.align_to_uninit_mut::<T>().1[0])
        }
        pub fn try_alloc_u32(&mut self, value: u32) -> Option<&'scope mut u32> {
            let uninit = self.try_alloc_uninit()?;
            Some(uninit.write(value))
        }
    }

    let mut memory = [MaybeUninit::<u8>::uninit(); 10];
    let mut allocator = BumpAllocator::new(&mut memory);
    let v = allocator.try_alloc_u32(42);
    assert_eq!(v, Some(&mut 42));

Source§

### impl<T, const N: usize> [[T; N]]

1.80.0 (const: 1.87.0) · Source

#### pub const fn as_flattened(&self) -> &[T]

Takes a `&[[T; N]]`, and flattens it to a `&[T]`.

For the opposite operation, see `as_chunks` and `as_rchunks`.

##### §Panics

This panics if the length of the resulting slice would overflow a `usize`.

This is only possible when flattening a slice of arrays of zero-sized types, and thus tends to be irrelevant in practice. If `size_of::<T>() > 0`, this will never panic.

##### §Examples

    assert_eq!([[1, 2, 3], [4, 5, 6]].as_flattened(), &[1, 2, 3, 4, 5, 6]);

    assert_eq!(
        [[1, 2, 3], [4, 5, 6]].as_flattened(),
        [[1, 2], [3, 4], [5, 6]].as_flattened(),
    );

    let slice_of_empty_arrays: &[[i32; 0]] = &[[], [], [], [], []];
    assert!(slice_of_empty_arrays.as_flattened().is_empty());

    let empty_slice_of_arrays: &[[u32; 10]] = &[];
    assert!(empty_slice_of_arrays.as_flattened().is_empty());

1.80.0 (const: 1.87.0) · Source

#### pub const fn as_flattened_mut(&mut self) -> &mut [T]

Takes a `&mut [[T; N]]`, and flattens it to a `&mut [T]`.

For the opposite operation, see `as_chunks_mut` and `as_rchunks_mut`.

##### §Panics

This panics if the length of the resulting slice would overflow a `usize`.

This is only possible when flattening a slice of arrays of zero-sized types, and thus tends to be irrelevant in practice. If `size_of::<T>() > 0`, this will never panic.

##### §Examples

    fn add_5_to_all(slice: &mut [i32]) {
        for i in slice {
            *i += 5;
        }
    }

    let mut array = [[1, 2, 3], [4, 5, 6], [7, 8, 9]];
    add_5_to_all(array.as_flattened_mut());
    assert_eq!(array, [[6, 7, 8], [9, 10, 11], [12, 13, 14]]);

Source§

### impl [f32]

Source

#### pub fn sort_floats(&mut self)

🔬This is a nightly-only experimental API. (`sort_floats` #93396)

Sorts the slice of floats.

This sort is in-place (i.e. does not allocate), O(n * log(n)) worst-case, and uses the ordering defined by `f32::total_cmp`.

##### §Current implementation

This uses the same sorting algorithm as `sort_unstable_by`.

##### §Examples

    #![feature(sort_floats)]
    let mut v = [2.6, -5e-8, f32::NAN, 8.29, f32::INFINITY, -1.0, 0.0, -f32::INFINITY, -0.0];

    v.sort_floats();
    let sorted = [-f32::INFINITY, -1.0, -5e-8, -0.0, 0.0, 2.6, 8.29, f32::INFINITY, f32::NAN];
    assert_eq!(&v[..8], &sorted[..8]);
    assert!(v[8].is_nan());

Source§

### impl [f64]

Source

#### pub fn sort_floats(&mut self)

🔬This is a nightly-only experimental API. (`sort_floats` #93396)

Sorts the slice of floats.

This sort is in-place (i.e. does not allocate), O(n * log(n)) worst-case, and uses the ordering defined by `f64::total_cmp`.

##### §Current implementation

This uses the same sorting algorithm as `sort_unstable_by`.

##### §Examples

    #![feature(sort_floats)]
    let mut v = [2.6, -5e-8, f64::NAN, 8.29, f64::INFINITY, -1.0, 0.0, -f64::INFINITY, -0.0];

    v.sort_floats();
    let sorted = [-f64::INFINITY, -1.0, -5e-8, -0.0, 0.0, 2.6, 8.29, f64::INFINITY, f64::NAN];
    assert_eq!(&v[..8], &sorted[..8]);
    assert!(v[8].is_nan());

Source§

### impl [u8]

1.79.0 · Source

#### pub fn utf8_chunks(&self) -> Utf8Chunks<'_> ⓘ

Creates an iterator over the contiguous valid UTF-8 ranges of this slice, and the non-UTF-8 fragments in between.

See the `Utf8Chunk` type for documentation of the items yielded by this iterator.

##### §Examples

This function formats arbitrary but mostly-UTF-8 bytes into Rust source code in the form of a C-string literal (`c"..."`).

    use std::fmt::Write as _;

    pub fn cstr_literal(bytes: &[u8]) -> String {
        let mut repr = String::new();
        repr.push_str("c\"");
        for chunk in bytes.utf8_chunks() {
            for ch in chunk.valid().chars() {
                // Escapes \0, \t, \r, \n, \\, \', \", and uses \u{...} for non-printable characters.
                write!(repr, "{}", ch.escape_debug()).unwrap();
            }
            for byte in chunk.invalid() {
                write!(repr, "\\x{:02X}", byte).unwrap();
            }
        }
        repr.push('"');
        repr
    }

    fn main() {
        let lit = cstr_literal(b"\xferris the \xf0\x9f\xa6\x80\x07");
        let expected = stringify!(c"\xFErris the 🦀\u{7}");
        assert_eq!(lit, expected);
    }

## Trait Implementations§

1.0.0 · Source§

### impl<T> AsMut<[T]> for [T]

Source§

#### fn as_mut(&mut self) -> &mut [T]

Converts this type into a mutable reference of the (usually inferred) input type.
1.0.0 · Source§

### impl<T, const N: usize> AsMut<[T]> for [T; N]

Source§

#### fn as_mut(&mut self) -> &mut [T]

Converts this type into a mutable reference of the (usually inferred) input type.
Source§

### impl<T, const N: usize> AsMut<[T]> for Simd<T, N>
where LaneCount<N>: SupportedLaneCount, T: SimdElement,

Source§

#### fn as_mut(&mut self) -> &mut [T]

Converts this type into a mutable reference of the (usually inferred) input type.
Source§

### impl AsMut<[u8]> for ByteStr

Source§

#### fn as_mut(&mut self) -> &mut [u8]

Converts this type into a mutable reference of the (usually inferred) input type.
1.0.0 · Source§

### impl<T> AsRef<[T]> for [T]

Source§

#### fn as_ref(&self) -> &[T]

Converts this type into a shared reference of the (usually inferred) input type.
1.0.0 · Source§

### impl<T, const N: usize> AsRef<[T]> for [T; N]

Source§

#### fn as_ref(&self) -> &[T]

Converts this type into a shared reference of the (usually inferred) input type.
1.13.0 · Source§

### impl<T> AsRef<[T]> for Iter<'_, T>

Source§

#### fn as_ref(&self) -> &[T]

Converts this type into a shared reference of the (usually inferred) input type.
1.53.0 · Source§

### impl<T> AsRef<[T]> for IterMut<'_, T>

Source§

#### fn as_ref(&self) -> &[T]

Converts this type into a shared reference of the (usually inferred) input type.
Source§

### impl<T, const N: usize> AsRef<[T]> for Simd<T, N>
where LaneCount<N>: SupportedLaneCount, T: SimdElement,

Source§

#### fn as_ref(&self) -> &[T]

Converts this type into a shared reference of the (usually inferred) input type.
Source§

### impl AsRef<[u8]> for ByteStr

Source§

#### fn as_ref(&self) -> &[u8]

Converts this type into a shared reference of the (usually inferred) input type.
1.0.0 · Source§

### impl AsRef<[u8]> for str

Source§

#### fn as_ref(&self) -> &[u8]

Converts this type into a shared reference of the (usually inferred) input type.
1.4.0 · Source§

### impl<T, const N: usize> Borrow<[T]> for [T; N]

Source§

#### fn borrow(&self) -> &[T]

Immutably borrows from an owned value. Read more
Source§

### impl Borrow<[u8]> for ByteStr

Source§

#### fn borrow(&self) -> &[u8]

Immutably borrows from an owned value. Read more
1.4.0 · Source§

### impl<T, const N: usize> BorrowMut<[T]> for [T; N]

Source§

#### fn borrow_mut(&mut self) -> &mut [T]

Mutably borrows from an owned value. Read more
Source§

### impl BorrowMut<[u8]> for ByteStr

Source§

#### fn borrow_mut(&mut self) -> &mut [u8]

Mutably borrows from an owned value. Read more
Source§

### impl<T: Clone> CloneToUninit for [T]

Source§

#### unsafe fn clone_to_uninit(&self, dest: *mut u8)

🔬This is a nightly-only experimental API. (`clone_to_uninit` #126799)
Performs copy-assignment from `self` to `dest`. Read more
1.0.0 · Source§

### impl<T: Debug> Debug for [T]

Source§

#### fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more
1.0.0 · Source§

### impl<T> Default for &[T]

Source§

#### fn default() -> Self

Creates an empty slice.

1.5.0 · Source§

### impl<T> Default for &mut [T]

Source§

#### fn default() -> Self

Creates a mutable empty slice.

Source§

### impl<'data> From<&'data mut [MaybeUninit<u8>]> for BorrowedBuf<'data>

Creates a new `BorrowedBuf` from an uninitialized buffer.

Use `set_init` if part of the buffer is known to be already initialized.

Source§

#### fn from(buf: &'data mut [MaybeUninit<u8>]) -> BorrowedBuf<'data>

Converts to this type from the input type.
Source§

### impl<'data> From<&'data mut [u8]> for BorrowedBuf<'data>

Creates a new `BorrowedBuf` from a fully initialized slice.

Source§

#### fn from(slice: &'data mut [u8]) -> BorrowedBuf<'data>

Converts to this type from the input type.
1.0.0 · Source§

### impl<T: Hash> Hash for [T]

Source§

#### fn hash<H: Hasher>(&self, state: &mut H)

Feeds this value into the given `Hasher`. Read more
1.0.0 · Source§

### impl<T, I> Index<I> for [T]
where I: SliceIndex<[T]>,

Source§

#### type Output = <I as SliceIndex<[T]>>::Output

The returned type after indexing.
Source§

#### fn index(&self, index: I) -> &I::Output

Performs the indexing (`container[index]`) operation. Read more
1.0.0 · Source§

### impl<T, I> IndexMut<I> for [T]
where I: SliceIndex<[T]>,

Source§

#### fn index_mut(&mut self, index: I) -> &mut I::Output

Performs the mutable indexing (`container[index]`) operation. Read more
1.0.0 · Source§

### impl<'a, T> IntoIterator for &'a [T]

Source§

#### type Item = &'a T

The type of the elements being iterated over.
Source§

#### type IntoIter = Iter<'a, T>

Which kind of iterator are we turning this into?
Source§

#### fn into_iter(self) -> Iter<'a, T> ⓘ

Creates an iterator from a value. Read more
1.0.0 · Source§

### impl<'a, T> IntoIterator for &'a mut [T]

Source§

#### type Item = &'a mut T

The type of the elements being iterated over.
Source§

#### type IntoIter = IterMut<'a, T>

Which kind of iterator are we turning this into?
Source§

#### fn into_iter(self) -> IterMut<'a, T> ⓘ

Creates an iterator from a value. Read more
1.0.0 · Source§

### impl<T: Ord> Ord for [T]

Implements comparison of slices lexicographically.

Source§

#### fn cmp(&self, other: &[T]) -> Ordering

This method returns an `Ordering` between `self` and `other`. Read more
1.0.0 · Source§

### impl<T, U, const N: usize> PartialEq<&[U]> for [T; N]
where T: PartialEq<U>,

Source§

#### fn eq(&self, other: &&[U]) -> bool

Tests for `self` and `other` values to be equal, and is used by `==`.
Source§

#### fn ne(&self, other: &&[U]) -> bool

Tests for `!=`. The default implementation is almost always sufficient, and should not be overridden without very good reason.
Source§

### impl<'a> PartialEq<&[u8]> for ByteStr

Source§

#### fn eq(&self, other: &&[u8]) -> bool

Tests for `self` and `other` values to be equal, and is used by `==`.
1.0.0 · Source§

#### fn ne(&self, other: &Rhs) -> bool

Tests for `!=`. The default implementation is almost always sufficient, and should not be overridden without very good reason.
1.0.0 · Source§

### impl<T, U, const N: usize> PartialEq<&mut [U]> for [T; N]
where T: PartialEq<U>,

Source§

#### fn eq(&self, other: &&mut [U]) -> bool

Tests for `self` and `other` values to be equal, and is used by `==`.
Source§

#### fn ne(&self, other: &&mut [U]) -> bool

Tests for `!=`. The default implementation is almost always sufficient, and should not be overridden without very good reason.
1.0.0 · Source§

### impl<T, U> PartialEq<[U]> for [T]
where T: PartialEq<U>,

Source§

#### fn eq(&self, other: &[U]) -> bool

Tests for `self` and `other` values to be equal, and is used by `==`.
Source§

#### fn ne(&self, other: &[U]) -> bool

Tests for `!=`. The default implementation is almost always sufficient, and should not be overridden without very good reason.
1.0.0 · Source§

### impl<T, U, const N: usize> PartialEq<[U]> for [T; N]
where T: PartialEq<U>,

Source§

#### fn eq(&self, other: &[U]) -> bool

Tests for `self` and `other` values to be equal, and is used by `==`.
Source§

#### fn ne(&self, other: &[U]) -> bool

Tests for `!=`. The default implementation is almost always sufficient, and should not be overridden without very good reason.
1.0.0 · Source§

### impl<T, U, const N: usize> PartialEq<[U; N]> for &[T]
where T: PartialEq<U>,

Source§

#### fn eq(&self, other: &[U; N]) -> bool

Tests for `self` and `other` values to be equal, and is used by `==`.
Source§

#### fn ne(&self, other: &[U; N]) -> bool

Tests for `!=`. The default implementation is almost always sufficient, and should not be overridden without very good reason.
1.0.0 · Source§

### impl<T, U, const N: usize> PartialEq<[U; N]> for &mut [T]
where T: PartialEq<U>,

Source§

#### fn eq(&self, other: &[U; N]) -> bool

Tests for `self` and `other` values to be equal, and is used by `==`.
Source§

#### fn ne(&self, other: &[U; N]) -> bool

Tests for `!=`. The default implementation is almost always sufficient, and should not be overridden without very good reason.
1.0.0 · Source§

### impl<T, U, const N: usize> PartialEq<[U; N]> for [T]
where T: PartialEq<U>,

Source§

#### fn eq(&self, other: &[U; N]) -> bool

Tests for `self` and `other` values to be equal, and is used by `==`.
Source§

#### fn ne(&self, other: &[U; N]) -> bool

Tests for `!=`. The default implementation is almost always sufficient, and should not be overridden without very good reason.
Source§

### impl<'a> PartialEq<[u8]> for ByteStr

Source§

#### fn eq(&self, other: &[u8]) -> bool

Tests for `self` and `other` values to be equal, and is used by `==`.
1.0.0 · Source§

#### fn ne(&self, other: &Rhs) -> bool

Tests for `!=`. The default implementation is almost always sufficient, and should not be overridden without very good reason.
Source§

### impl<'a> PartialEq<ByteStr> for &[u8]

Source§

#### fn eq(&self, other: &ByteStr) -> bool

Tests for `self` and `other` values to be equal, and is used by `==`.
1.0.0 · Source§

#### fn ne(&self, other: &Rhs) -> bool

Tests for `!=`. The default implementation is almost always sufficient, and should not be overridden without very good reason.
Source§

### impl<'a> PartialEq<ByteStr> for [u8]

Source§

#### fn eq(&self, other: &ByteStr) -> bool

Tests for `self` and `other` values to be equal, and is used by `==`.
1.0.0 · Source§

#### fn ne(&self, other: &Rhs) -> bool

Tests for `!=`. The default implementation is almost always sufficient, and should not be overridden without very good reason.
1.0.0 · Source§

### impl<T: PartialOrd> PartialOrd for [T]

Implements comparison of slices lexicographically.

Source§

#### fn partial_cmp(&self, other: &[T]) -> Option<Ordering>

This method returns an ordering between `self` and `other` values if one exists. Read more
Source§

#### fn lt(&self, other: &Self) -> bool

Tests less than (for `self` and `other`) and is used by the `<` operator. Read more
Source§

#### fn le(&self, other: &Self) -> bool

Tests less than or equal to (for `self` and `other`) and is used by the `<=` operator. Read more
Source§

#### fn gt(&self, other: &Self) -> bool

Tests greater than (for `self` and `other`) and is used by the `>` operator. Read more
Source§

#### fn ge(&self, other: &Self) -> bool

Tests greater than or equal to (for `self` and `other`) and is used by the `>=` operator. Read more
Source§

### impl<'b> Pattern for &'b [char]

Searches for chars that are equal to any of the `char`s in the slice.

#### §Examples

    assert_eq!("Hello world".find(&['o', 'l'][..]), Some(2));
    assert_eq!("Hello world".find(&['h', 'w'][..]), Some(6));

Source§

#### type Searcher<'a> = CharSliceSearcher<'a, 'b>

🔬This is a nightly-only experimental API. (`pattern` #27721)
Associated searcher for this pattern
Source§

#### fn into_searcher<'a>(self, haystack: &'a str) -> CharSliceSearcher<'a, 'b>

🔬This is a nightly-only experimental API. (`pattern` #27721)
Constructs the associated searcher from `self` and the `haystack` to search in.
Source§

#### fn is_contained_in<'a>(self, haystack: &'a str) -> bool

🔬This is a nightly-only experimental API. (`pattern` #27721)
Checks whether the pattern matches anywhere in the haystack
Source§

#### fn is_prefix_of<'a>(self, haystack: &'a str) -> bool

🔬This is a nightly-only experimental API. (`pattern` #27721)
Checks whether the pattern matches at the front of the haystack
Source§

#### fn strip_prefix_of<'a>(self, haystack: &'a str) -> Option<&'a str>

🔬This is a nightly-only experimental API. (`pattern` #27721)
Removes the pattern from the front of haystack, if it matches.
Source§

#### fn is_suffix_of<'a>(self, haystack: &'a str) -> bool
where CharSliceSearcher<'a, 'b>: ReverseSearcher<'a>,

🔬This is a nightly-only experimental API. (`pattern` #27721)
Checks whether the pattern matches at the back of the haystack
Source§

#### fn strip_suffix_of<'a>(self, haystack: &'a str) -> Option<&'a str>
where CharSliceSearcher<'a, 'b>: ReverseSearcher<'a>,

🔬This is a nightly-only experimental API. (`pattern` #27721)
Removes the pattern from the back of haystack, if it matches.
Source§

#### fn as_utf8_pattern(&self) -> Option<Utf8Pattern<'_>>

🔬This is a nightly-only experimental API. (`pattern` #27721)
Returns the pattern as utf-8 bytes if possible.
1.53.0 · Source§

### impl<T> SliceIndex<[T]> for (Bound<usize>, Bound<usize>)

Source§

#### type Output = [T]

The output type returned by methods.
Source§

#### fn get(self, slice: &[T]) -> Option<&Self::Output>

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, if in bounds.
Source§

#### fn get_mut(self, slice: &mut [T]) -> Option<&mut Self::Output>

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, if in bounds.
Source§

#### unsafe fn get_unchecked(self, slice: *const [T]) -> *const Self::Output

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a pointer to the output at this location, without performing any bounds checking. Read more
Source§

#### unsafe fn get_unchecked_mut(self, slice: *mut [T]) -> *mut Self::Output

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable pointer to the output at this location, without performing any bounds checking. Read more
Source§

#### fn index(self, slice: &[T]) -> &Self::Output

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, panicking if out of bounds.
Source§

#### fn index_mut(self, slice: &mut [T]) -> &mut Self::Output

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, panicking if out of bounds.
1.15.0 · Source§

### impl<T> SliceIndex<[T]> for Range<usize>

The methods `index` and `index_mut` panic if:

- the start of the range is greater than the end of the range or
- the end of the range is out of bounds.

Source§

#### type Output = [T]

The output type returned by methods.
Source§

#### fn get(self, slice: &[T]) -> Option<&[T]>

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, if in bounds.
Source§

#### fn get_mut(self, slice: &mut [T]) -> Option<&mut [T]>

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, if in bounds.
Source§

#### unsafe fn get_unchecked(self, slice: *const [T]) -> *const [T]

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a pointer to the output at this location, without performing any bounds checking. Read more
Source§

#### unsafe fn get_unchecked_mut(self, slice: *mut [T]) -> *mut [T]

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable pointer to the output at this location, without performing any bounds checking. Read more
Source§

#### fn index(self, slice: &[T]) -> &[T]

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, panicking if out of bounds.
Source§

#### fn index_mut(self, slice: &mut [T]) -> &mut [T]

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, panicking if out of bounds.
Source§

### impl<T> SliceIndex<[T]> for Range<usize>

Source§

#### type Output = [T]

The output type returned by methods.
Source§

#### fn get(self, slice: &[T]) -> Option<&[T]>

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, if in bounds.
Source§

#### fn get_mut(self, slice: &mut [T]) -> Option<&mut [T]>

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, if in bounds.
Source§

#### unsafe fn get_unchecked(self, slice: *const [T]) -> *const [T]

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a pointer to the output at this location, without performing any bounds checking. Read more
Source§

#### unsafe fn get_unchecked_mut(self, slice: *mut [T]) -> *mut [T]

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable pointer to the output at this location, without performing any bounds checking. Read more
Source§

#### fn index(self, slice: &[T]) -> &[T]

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, panicking if out of bounds.
Source§

#### fn index_mut(self, slice: &mut [T]) -> &mut [T]

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, panicking if out of bounds.
1.15.0 · Source§

### impl<T> SliceIndex<[T]> for RangeFrom<usize>

The methods `index` and `index_mut` panic if the start of the range is out of bounds.

Source§

#### type Output = [T]

The output type returned by methods.
Source§

#### fn get(self, slice: &[T]) -> Option<&[T]>

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, if in bounds.
Source§

#### fn get_mut(self, slice: &mut [T]) -> Option<&mut [T]>

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, if in bounds.
Source§

#### unsafe fn get_unchecked(self, slice: *const [T]) -> *const [T]

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a pointer to the output at this location, without performing any bounds checking. Read more
Source§

#### unsafe fn get_unchecked_mut(self, slice: *mut [T]) -> *mut [T]

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable pointer to the output at this location, without performing any bounds checking. Read more
Source§

#### fn index(self, slice: &[T]) -> &[T]

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, panicking if out of bounds.
Source§

#### fn index_mut(self, slice: &mut [T]) -> &mut [T]

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, panicking if out of bounds.
Source§

### impl<T> SliceIndex<[T]> for RangeFrom<usize>

Source§

#### type Output = [T]

The output type returned by methods.
Source§

#### fn get(self, slice: &[T]) -> Option<&[T]>

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, if in bounds.
Source§

#### fn get_mut(self, slice: &mut [T]) -> Option<&mut [T]>

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, if in bounds.
Source§

#### unsafe fn get_unchecked(self, slice: *const [T]) -> *const [T]

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a pointer to the output at this location, without performing any bounds checking. Read more
Source§

#### unsafe fn get_unchecked_mut(self, slice: *mut [T]) -> *mut [T]

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable pointer to the output at this location, without performing any bounds checking. Read more
Source§

#### fn index(self, slice: &[T]) -> &[T]

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, panicking if out of bounds.
Source§

#### fn index_mut(self, slice: &mut [T]) -> &mut [T]

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, panicking if out of bounds.
1.15.0 · Source§

### impl<T> SliceIndex<[T]> for RangeFull

Source§

#### type Output = [T]

The output type returned by methods.
Source§

#### fn get(self, slice: &[T]) -> Option<&[T]>

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, if in bounds.
Source§

#### fn get_mut(self, slice: &mut [T]) -> Option<&mut [T]>

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, if in bounds.
Source§

#### unsafe fn get_unchecked(self, slice: *const [T]) -> *const [T]

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a pointer to the output at this location, without performing any bounds checking. Read more
Source§

#### unsafe fn get_unchecked_mut(self, slice: *mut [T]) -> *mut [T]

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable pointer to the output at this location, without performing any bounds checking. Read more
Source§

#### fn index(self, slice: &[T]) -> &[T]

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, panicking if out of bounds.
Source§

#### fn index_mut(self, slice: &mut [T]) -> &mut [T]

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, panicking if out of bounds.
1.26.0 · Source§

### impl<T> SliceIndex<[T]> for RangeInclusive<usize>

The methods `index` and `index_mut` panic if:

- the end of the range is `usize::MAX` or
- the start of the range is greater than the end of the range or
- the end of the range is out of bounds.

Source§

#### type Output = [T]

The output type returned by methods.
Source§

#### fn get(self, slice: &[T]) -> Option<&[T]>

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, if in bounds.
Source§

#### fn get_mut(self, slice: &mut [T]) -> Option<&mut [T]>

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, if in bounds.
Source§

#### unsafe fn get_unchecked(self, slice: *const [T]) -> *const [T]

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a pointer to the output at this location, without performing any bounds checking. Read more
Source§

#### unsafe fn get_unchecked_mut(self, slice: *mut [T]) -> *mut [T]

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable pointer to the output at this location, without performing any bounds checking. Read more
Source§

#### fn index(self, slice: &[T]) -> &[T]

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, panicking if out of bounds.
Source§

#### fn index_mut(self, slice: &mut [T]) -> &mut [T]

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, panicking if out of bounds.
Source§

### impl<T> SliceIndex<[T]> for RangeInclusive<usize>

Source§

#### type Output = [T]

The output type returned by methods.
Source§

#### fn get(self, slice: &[T]) -> Option<&[T]>

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, if in bounds.
Source§

#### fn get_mut(self, slice: &mut [T]) -> Option<&mut [T]>

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, if in bounds.
Source§

#### unsafe fn get_unchecked(self, slice: *const [T]) -> *const [T]

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a pointer to the output at this location, without performing any bounds checking. Read more
Source§

#### unsafe fn get_unchecked_mut(self, slice: *mut [T]) -> *mut [T]

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable pointer to the output at this location, without performing any bounds checking. Read more
Source§

#### fn index(self, slice: &[T]) -> &[T]

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, panicking if out of bounds.
Source§

#### fn index_mut(self, slice: &mut [T]) -> &mut [T]

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, panicking if out of bounds.
1.15.0 · Source§

### impl<T> SliceIndex<[T]> for RangeTo<usize>

The methods `index` and `index_mut` panic if the end of the range is out of bounds.

Source§

#### type Output = [T]

The output type returned by methods.
Source§

#### fn get(self, slice: &[T]) -> Option<&[T]>

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, if in bounds.
Source§

#### fn get_mut(self, slice: &mut [T]) -> Option<&mut [T]>

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, if in bounds.
Source§

#### unsafe fn get_unchecked(self, slice: *const [T]) -> *const [T]

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a pointer to the output at this location, without performing any bounds checking. Read more
Source§

#### unsafe fn get_unchecked_mut(self, slice: *mut [T]) -> *mut [T]

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable pointer to the output at this location, without performing any bounds checking. Read more
Source§

#### fn index(self, slice: &[T]) -> &[T]

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, panicking if out of bounds.
Source§

#### fn index_mut(self, slice: &mut [T]) -> &mut [T]

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, panicking if out of bounds.
1.26.0 · Source§

### impl<T> SliceIndex<[T]> for RangeToInclusive<usize>

The methods `index` and `index_mut` panic if the end of the range is out of bounds.

Source§

#### type Output = [T]

The output type returned by methods.
Source§

#### fn get(self, slice: &[T]) -> Option<&[T]>

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, if in bounds.
Source§

#### fn get_mut(self, slice: &mut [T]) -> Option<&mut [T]>

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, if in bounds.
Source§

#### unsafe fn get_unchecked(self, slice: *const [T]) -> *const [T]

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a pointer to the output at this location, without performing any bounds checking. Read more
Source§

#### unsafe fn get_unchecked_mut(self, slice: *mut [T]) -> *mut [T]

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable pointer to the output at this location, without performing any bounds checking. Read more
Source§

#### fn index(self, slice: &[T]) -> &[T]

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, panicking if out of bounds.
Source§

#### fn index_mut(self, slice: &mut [T]) -> &mut [T]

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, panicking if out of bounds.
1.15.0 · Source§

### impl<T> SliceIndex<[T]> for usize

The methods `index` and `index_mut` panic if the index is out of bounds.

Source§

#### type Output = T

The output type returned by methods.
Source§

#### fn get(self, slice: &[T]) -> Option<&T>

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, if in bounds.
Source§

#### fn get_mut(self, slice: &mut [T]) -> Option<&mut T>

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, if in bounds.
Source§

#### unsafe fn get_unchecked(self, slice: *const [T]) -> *const T

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a pointer to the output at this location, without performing any bounds checking. Read more
Source§

#### unsafe fn get_unchecked_mut(self, slice: *mut [T]) -> *mut T

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable pointer to the output at this location, without performing any bounds checking. Read more
Source§

#### fn index(self, slice: &[T]) -> &T

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, panicking if out of bounds.
Source§

#### fn index_mut(self, slice: &mut [T]) -> &mut T

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, panicking if out of bounds.
1.51.0 · Source§

### impl<T> SlicePattern for [T]

Source§

#### type Item = T

🔬This is a nightly-only experimental API. (`slice_pattern` #56345)
The element type of the slice being matched on.
Source§

#### fn as_slice(&self) -> &[Self::Item]

🔬This is a nightly-only experimental API. (`slice_pattern` #56345)
Currently, the consumers of `SlicePattern` need a slice.
1.34.0 · Source§

### impl<'a, T, const N: usize> TryFrom<&'a [T]> for &'a [T; N]

Tries to create an array ref `&[T; N]` from a slice ref `&[T]`. Succeeds if `slice.len() == N`.

    let bytes: [u8; 3] = [1, 0, 2];

    let bytes_head: &[u8; 2] = <&[u8; 2]>::try_from(&bytes[0..2]).unwrap();
    assert_eq!(1, u16::from_le_bytes(*bytes_head));

    let bytes_tail: &[u8; 2] = bytes[1..3].try_into().unwrap();
    assert_eq!(512, u16::from_le_bytes(*bytes_tail));

Source§

#### type Error = TryFromSliceError

The type returned in the event of a conversion error.
Source§

#### fn try_from(slice: &'a [T]) -> Result<&'a [T; N], TryFromSliceError>

Performs the conversion.
1.34.0 · Source§

### impl<T, const N: usize> TryFrom<&[T]> for [T; N]
where T: Copy,

Tries to create an array `[T; N]` by copying from a slice `&[T]`. Succeeds if `slice.len() == N`.

    let bytes: [u8; 3] = [1, 0, 2];

    let bytes_head: [u8; 2] = <[u8; 2]>::try_from(&bytes[0..2]).unwrap();
    assert_eq!(1, u16::from_le_bytes(bytes_head));

    let bytes_tail: [u8; 2] = bytes[1..3].try_into().unwrap();
    assert_eq!(512, u16::from_le_bytes(bytes_tail));

Source§

#### type Error = TryFromSliceError

The type returned in the event of a conversion error.
Source§

#### fn try_from(slice: &[T]) -> Result<[T; N], TryFromSliceError>

Performs the conversion.
Source§

### impl<T, const N: usize> TryFrom<&[T]> for Simd<T, N>
where LaneCount<N>: SupportedLaneCount, T: SimdElement,

Source§

#### type Error = TryFromSliceError

The type returned in the event of a conversion error.
Source§

#### fn try_from(slice: &[T]) -> Result<Self, TryFromSliceError>

Performs the conversion.
1.34.0 · Source§

### impl<'a, T, const N: usize> TryFrom<&'a mut [T]> for &'a mut [T; N]

Tries to create a mutable array ref `&mut [T; N]` from a mutable slice ref `&mut [T]`. Succeeds if `slice.len() == N`.

    let mut bytes: [u8; 3] = [1, 0, 2];

    let bytes_head: &mut [u8; 2] = <&mut [u8; 2]>::try_from(&mut bytes[0..2]).unwrap();
    assert_eq!(1, u16::from_le_bytes(*bytes_head));

    let bytes_tail: &mut [u8; 2] = (&mut bytes[1..3]).try_into().unwrap();
    assert_eq!(512, u16::from_le_bytes(*bytes_tail));

Source§

#### type Error = TryFromSliceError

The type returned in the event of a conversion error.
Source§

#### fn try_from(slice: &'a mut [T]) -> Result<&'a mut [T; N], TryFromSliceError>

Performs the conversion.
1.59.0 · Source§

### impl<T, const N: usize> TryFrom<&mut [T]> for [T; N]
where T: Copy,

Tries to create an array `[T; N]` by copying from a mutable slice `&mut [T]`. Succeeds if `slice.len() == N`.

    let mut bytes: [u8; 3] = [1, 0, 2];

    let bytes_head: [u8; 2] = <[u8; 2]>::try_from(&mut bytes[0..2]).unwrap();
    assert_eq!(1, u16::from_le_bytes(bytes_head));

    let bytes_tail: [u8; 2] = (&mut bytes[1..3]).try_into().unwrap();
    assert_eq!(512, u16::from_le_bytes(bytes_tail));

Source§

#### type Error = TryFromSliceError

The type returned in the event of a conversion error.
Source§

#### fn try_from(slice: &mut [T]) -> Result<[T; N], TryFromSliceError>

Performs the conversion.
Source§

### impl<T, const N: usize> TryFrom<&mut [T]> for Simd<T, N>
where LaneCount<N>: SupportedLaneCount, T: SimdElement,

Source§

#### type Error = TryFromSliceError

The type returned in the event of a conversion error.
Source§

#### fn try_from(slice: &mut [T]) -> Result<Self, TryFromSliceError>

Performs the conversion.
1.0.0 · Source§

### impl<T: Eq> Eq for [T]

1.80.0 · Source§

### impl<T> !Iterator for [T]

Source§

### impl<T> StructuralPartialEq for [T]

Source§

### impl<T: UnsizedConstParamTy> UnsizedConstParamTy for [T]

## Auto Trait Implementations§

§

### impl<T> Freeze for [T]
where T: Freeze,

§

### impl<T> RefUnwindSafe for [T]
where T: RefUnwindSafe,

§

### impl<T> Send for [T]
where T: Send,

§

### impl<T> !Sized for [T]

§

### impl<T> Sync for [T]
where T: Sync,

§

### impl<T> Unpin for [T]
where T: Unpin,

§

### impl<T> UnwindSafe for [T]
where T: UnwindSafe,

## Blanket Implementations§

Source§

### impl<T> Any for T
where T: 'static + ?Sized,

Source§

#### fn type_id(&self) -> TypeId

Gets the `TypeId` of `self`. Read more
Source§

### impl<T> Borrow<T> for T
where T: ?Sized,

Source§

#### fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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### impl<T> BorrowMut<T> for T
where T: ?Sized,

Source§

#### fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more