NAME¶

Perl::Critic::Policy::Community::Each - Don't use each to iterate through a hash

DESCRIPTION¶

The each() function relies on an iterator internal to a hash (or array), which is the same iterator used by keys() and values(). So deleting or adding hash elements during iteration, or just calling keys() or values() on the hash, will cause undefined behavior and the code will likely break. This could occur even by passing the hash to other functions which operate on the hash. Instead, use a "foreach" loop iterating through the keys or values of the hash.

  while (my ($key, $value) = each %hash) { ... }                # not ok
  foreach my $key (keys %hash) { my $value = $hash{$key}; ... } # ok
  foreach my $i (0..$#array) { my $elem = $array[$i]; ... }     # ok

AFFILIATION¶

This policy is part of Perl::Critic::Community.

CONFIGURATION¶

This policy is not configurable except for the standard options.

AUTHOR¶

Dan Book, "dbook@cpan.org"

COPYRIGHT AND LICENSE¶

Copyright 2015, Dan Book.

This library is free software; you may redistribute it and/or modify it under the terms of the Artistic License version 2.0.

SEE ALSO¶

Perl::Critic, <http://blogs.perl.org/users/rurban/2014/04/do-not-use-each.html>