|. Reverse - Rotate (Shift)

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Reverse | |. _ 1 _ | Rotate

`|. y` reverses the order of the items of`y` .`` For example:
       |. t=: 'abcdefg'
    gfedcba
The right shift is the dyadic case of`|.!.f` with the left argument`_1` .`` For example:
       |.!.'#' t
    #abcdef

       |.!.10 i.3 3
    10 10 10
     0  1  2
     3  4  5
|  | `x|.y` rotates successive axes of`y` by successive elements of`x` .`` Thus:
       1 2 |. i. 3 5
     7  8  9  5  6
    12 13 14 10 11
     2  3  4  0  1
The phrase`x |.!.f y` produces a shift: the items normally brought around by the cyclic rotation are replaced by`f` unless`f` is empty`` (`0=#f`),`` in which case they are replaced by the normal fill defined under Take (`{.`):
       2 _2 |.!.'#'"0 1 t
    cdefg##
    ##abcde

       y=: a.{~ (a. i. 'A') + i. 5 6

       (] ; 2&|. ; _2&|. ; 2&|."1  ; 2&(|.!.'*'"1)) y
    +------+------+------+------+------+
    |ABCDEF|MNOPQR|STUVWX|CDEFAB|CDEF**|
    |GHIJKL|STUVWX|YZ[\]^|IJKLGH|IJKL**|
    |MNOPQR|YZ[\]^|ABCDEF|OPQRMN|OPQR**|
    |STUVWX|ABCDEF|GHIJKL|UVWXST|UVWX**|
    |YZ[\]^|GHIJKL|MNOPQR|[\]^YZ|[\]^**|
    +------+------+------+------+------+

       (] ; |. ; |."1 ; |.!.'*'"1  ; (2: |. ])) y
    +------+------+------+------+------+
    |ABCDEF|YZ[\]^|FEDCBA|*ABCDE|MNOPQR|
    |GHIJKL|STUVWX|LKJIHG|*GHIJK|STUVWX|
    |MNOPQR|MNOPQR|RQPONM|*MNOPQ|YZ[\]^|
    |STUVWX|GHIJKL|XWVUTS|*STUVW|ABCDEF|
    |YZ[\]^|ABCDEF|^]\[ZY|*YZ[\]|GHIJKL|
    +------+------+------+------+------+

       1 _2 |. !. '*' 3{. y
    **GHIJ
    **MNOP
    ******

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