Perl Programming/Keywords/each

The each keyword

each returns a two-element list consisting of the key and value for the next element of a hash, if called on a hash in list context. In Perl 5.12 and later only, it returns the index and value for the next element of an array. For older Perl versions, this is considered as a syntax error. When called in scalar context, it returns only the key (not the value) in a hash, or the index in an array.

Syntax

  each ARRAY
  each EXPRESSION
  each HASH

Examples

The code

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

returns the environment as key-value pairs, separated by an assignment sign, like:

 USERPROFILE = C:\Users\<user name>
 USERDNSDOMAIN = <domain name>
 […]
 HOMEDRIVE = U:
 PATH = C:\Programms\Perl\site\bin;…
 […]
 SYSTEMDRIVE = C:
 […]
 USERNAME = <user name>
 […]

See also

• Conditionals