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# each

Perl 5 version 12.2 documentation
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# each

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

- each HASH

- each ARRAY

  When called in list context, returns a 2-element list consisting of the key and value for the next element of a hash, or the index and value for the next element of an array, so that you can iterate over it. When called in scalar context, returns only the key (not the value) in a hash, or the index in an array.

  Hash entries are returned in an apparently random order. The actual random order is subject to change in future versions of Perl, but it is guaranteed to be in the same order as either the `keys` or `values` function would produce on the same (unmodified) hash. Since Perl 5.8.2 the ordering can be different even between different runs of Perl for security reasons (see Algorithmic Complexity Attacks in perlsec).

  After `each` has returned all entries from the hash or array, the next call to `each` returns the empty list in list context and `undef` in scalar context. The next call following that one restarts iteration. Each hash or array has its own internal iterator, accessed by `each`, `keys`, and `values`. The iterator is implicitly reset when `each` has reached the end as just described; it can be explicitly reset by calling `keys` or `values` on the hash or array. If you add or delete a hash's elements while iterating over it, entries may be skipped or duplicated--so don't do that. Exception: It is always safe to delete the item most recently returned by `each()`, so the following code works properly:

              while (($key, $value) = each %hash) {          print $key, "\n";          delete $hash{$key};   # This is safe        }

  This prints out your environment like the printenv(1) program, but in a different order:

          while (($key,$value) = each %ENV) {        print "$key=$value\n";    }

  See also `keys`, `values` and `sort`.