Perl Programming/Keywords/keys

The keys keyword

The keys command returns all the keys the HASH has in an apparent random order, when called in list context. In Perl 5.12.0 or later, the indices of an ARRAY are returned.

As a side effect, keys resets the internal iterator of the ARRAY or HASH (see each). Calling it in void context resets the iterator with no other overhead.

Syntax

  keys HASH
  keys ARRAY
  keys EXPRESSION

Examples

%hash = (foo => 11, bar => 22, baz => 33);

print "keys, values\n";
@keys = keys %hash;
@values = values %hash;

while (@keys) {
  print pop(@keys), ' => ', pop(@values), "\n";
}

results in

keys, values
foo => 11
baz => 33
bar => 22

See also

• each
• values