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Full Discussion: PERL: simple comparing arrays question
Top Forums Shell Programming and Scripting PERL: simple comparing arrays question Post 302350983 by Vi-Curious on Sunday 6th of September 2009 05:34:03 PM
Old 09-06-2009
In your "if", what is the value of "$_"? Did you take a hash example and try to convert it to work on lists?

What you want to do in the if is iterate over the second list. One solution:

Code:
for my $name ( sort (@array1)) {
  my $found = 0;
  foreach (@array2) {
    if ( $name eq $_ ) { $found++; }
  }
  if ( $found ) {
    print "woo hoo $name exists in both arrays\n";
  } else {
    print "$name does not exist in array2\n";
  }
}

perl has a grep function which is supposed to iterate over the list for you so you might also look at that.
 

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LEARN ABOUT DEBIAN

perl::critic::policy::builtinfunctions::prohibitvoidgrep

Perl::Critic::Policy::BuiltinFunctions::ProhibitVoidGrepUser)Contributed Perl DocumenPerl::Critic::Policy::BuiltinFunctions::ProhibitVoidGrep(3pm)

NAME

       Perl::Critic::Policy::BuiltinFunctions::ProhibitVoidGrep - Don't use "grep" in void contexts.

AFFILIATION

       This Policy is part of the core Perl::Critic distribution.

DESCRIPTION

       "map" and "grep" are intended to be pure functions, not mutators.  If you want to iterate with side-effects, then you should use a proper
       "for" or "foreach" loop.

	   grep{ print frobulate($_) } @list;		#not ok
	   print map{ frobulate($_) } @list;		#ok

	   grep{ $_ = lc $_ } @list;			#not ok
	   for( @list ){ $_ = lc $_  }; 		#ok

	   map{ push @frobbed, frobulate($_) } @list;	#not ok
	   @frobbed = map { frobulate($_) } @list;	#ok

CONFIGURATION

       This Policy is not configurable except for the standard options.

AUTHOR

       Jeffrey Ryan Thalhammer <jeff@imaginative-software.com>

COPYRIGHT

       Copyright (c) 2005-2011 Imaginative Software Systems.  All rights reserved.

       This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.  The full text of this license
       can be found in the LICENSE file included with this module.

perl v5.14.2							    2012-06-07	     Perl::Critic::Policy::BuiltinFunctions::ProhibitVoidGrep(3pm)
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