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# shift

Perl 5 version 18.2 documentation
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# shift

Perl functions A-Z | Perl functions by category | The 'perlfunc' manpage

- shift ARRAY

- shift EXPR
- shift

  Shifts the first value of the array off and returns it, shortening the array by 1 and moving everything down. If there are no elements in the array, returns the undefined value. If ARRAY is omitted, shifts the `@_` array within the lexical scope of subroutines and formats, and the `@ARGV` array outside a subroutine and also within the lexical scopes established by the `eval STRING` , `BEGIN {}` , `INIT {}` , `CHECK {}` , `UNITCHECK {}` , and `END {}` constructs.

  Starting with Perl 5.14, `shift` can take a scalar EXPR, which must hold a reference to an unblessed array. The argument will be dereferenced automatically. This aspect of `shift` is considered highly experimental. The exact behaviour may change in a future version of Perl.

  To avoid confusing would-be users of your code who are running earlier versions of Perl with mysterious syntax errors, put this sort of thing at the top of your file to signal that your code will work only on Perls of a recent vintage:

          use 5.014;	# so push/pop/etc work on scalars (experimental)

  See also `unshift`, `push`, and `pop`. `shift` and `unshift` do the same thing to the left end of an array that `pop` and `push` do to the right end.