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# each

Perl 5 version 10.1 documentation
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# each

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

- each HASH

  When called in list context, returns a 2-element list consisting of the key and value for the next element of a hash, so that you can iterate over it. When called in scalar context, returns only the key for the next element in the 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).

  When the hash is entirely read, a null array is returned in list context (which when assigned produces a false (`0` ) value), and `undef` in scalar context. The next call to `each` after that will start iterating again. There is a single iterator for each hash, shared by all `each`, `keys`, and `values` function calls in the program; it can be reset by reading all the elements from the hash, or by evaluating `keys HASH` or `values HASH` . If you add or delete elements of a hash while you're iterating over it, you may get entries skipped or duplicated, so don't. Exception: It is always safe to delete the item most recently returned by `each()`, which means that the following code will work:

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

  The following prints out your environment like the printenv(1) program, only in a different order:

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

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

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