Computes the difference of arrays by using a callback function for data comparison

array_udiff_uassoc
array_uintersect_assoc
Array Functions
PHP Manual

# array_udiff

(PHP 5)

array_udiff — Computes the difference of arrays by using a callback function for data comparison

### Description

array array_udiff ( array `$array1` , array `$array2` [, array `$ ...` ], callback `$data_compare_func` )

Computes the difference of arrays by using a callback function for data comparison. This is unlike array_diff() which uses an internal function for comparing the data.

### Parameters

`array1`

  The first array.

`array2`

  The second array.

`data_compare_func`

  The callback comparison function.

  The user supplied callback function is used for comparison. It must return an integer less than, equal to, or greater than zero if the first argument is considered to be respectively less than, equal to, or greater than the second.

### Return Values

Returns an array containing all the values of `array1` that are not present in any of the other arguments.

### Examples

Example #1 array_udiff() example

`<?php
class cr {
private $priv_member;
function cr($val)
{
$this->priv_member = $val;
}
static function comp_func_cr($a, $b)
{
if ($a->priv_member === $b->priv_member) return 0;
return ($a->priv_member > $b->priv_member)? 1:-1;
}
}
$a = array("0.1" => new cr(9), "0.5" => new cr(12), 0 => new cr(23), 1=> new cr(4), 2 => new cr(-15),);
$b = array("0.2" => new cr(9), "0.5" => new cr(22), 0 => new cr(3), 1=> new cr(4), 2 => new cr(-15),);
$result = array_udiff($a, $b, array("cr", "comp_func_cr"));
print_r($result);
?>`

The above example will output:

    Array
    (
        [0.5] => cr Object
            (
                [priv_member:private] => 12
            )

        [0] => cr Object
            (
                [priv_member:private] => 23
            )

    )

### Notes

> Note: Please note that this function only checks one dimension of a n-dimensional array. Of course you can check deeper dimensions by using array_udiff($array1[0], $array2[0], "data_compare_func");.

### See Also

- array_diff() - Computes the difference of arrays
- array_diff_assoc() - Computes the difference of arrays with additional index check
- array_diff_uassoc() - Computes the difference of arrays with additional index check which is performed by a user supplied callback function
- array_udiff_assoc() - Computes the difference of arrays with additional index check, compares data by a callback function
- array_udiff_uassoc() - Computes the difference of arrays with additional index check, compares data and indexes by a callback function
- array_intersect() - Computes the intersection of arrays
- array_intersect_assoc() - Computes the intersection of arrays with additional index check
- array_uintersect() - Computes the intersection of arrays, compares data by a callback function
- array_uintersect_assoc() - Computes the intersection of arrays with additional index check, compares data by a callback function
- array_uintersect_uassoc() - Computes the intersection of arrays with additional index check, compares data and indexes by a callback functions

array_udiff_uassoc
array_uintersect_assoc
Array Functions
PHP Manual