array::diff(3pm) [debian man page]

Array::Diff(3pm)					User Contributed Perl Documentation					  Array::Diff(3pm)

NAME

       Array::Diff - Find the differences between two arrays

SYNOPSIS

	   my @old = ( 'a', 'b', 'c' );
	   my @new = ( 'b', 'c', 'd' );

	   my $diff = Array::Diff->diff( @old, @new );

	   $diff->count   # 2
	   $diff->added   # [ 'd' ];
	   $diff->deleted # [ 'a' ];

DESCRIPTION

       This module compares two arrays and returns the added or deleted elements in two separate arrays.  It's a simple wrapper around
       Algorithm::Diff.

       And if you need more complex array tools, check Array::Compare.

METHODS

       new ()
	   Create a new "Array::Diff" object.

       diff ( OLD, NEW )
	   Compute the differences between two arrays.	The results are stored in the "added", "deleted", and "count" properties that may be
	   examined using the corresponding methods.

	   This method may be invoked as an object method, in which case it will recalculate the differences and repopulate the "count", "added",
	   and "removed" properties, or as a static method, in which case it will return a newly-created "Array::Diff" object with the properies
	   set appropriately.

       added ( [VALUES ] )
	   Get or set the elements present in the "NEW" array and absent in the "OLD" one at the comparison performed by the last "diff()"
	   invocation.

       deleted ( [VALUES] )
	   Get or set the elements present in the "OLD" array and absent in the "NEW" one at the comparison performed by the last "diff()"
	   invocation.

       count ( [VALUE] )
	   Get or set the total number of added or deleted elements at the comparison performed by the last "diff()" invocation.  This count
	   should be equal to the sum of the number of elements in the "added" and "deleted" properties.

SEE ALSO

       Algorithm::Diff

AUTHOR

       Daisuke Murase <typester@cpan.org>

COPYRIGHT AND LICENSE

       Copyright (c) 2009 by Daisuke Murase.

       This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

       The full text of the license can be found in the LICENSE file included with this module.

perl v5.10.1							    2010-10-08							  Array::Diff(3pm)

Algorithm::DiffOld(3)					User Contributed Perl Documentation				     Algorithm::DiffOld(3)

NAME

       Algorithm::DiffOld - Compute `intelligent' differences between two files / lists but use the old (<=0.59) interface.

NOTE

       This has been provided as part of the Algorithm::Diff package by Ned Konz.  This particular module is ONLY for people who HAVE to have the
       old interface, which uses a comparison function rather than a key generating function.

       Because each of the lines in one array have to be compared with each of the lines in the other array, this does M*N comparisions. This can
       be very slow. I clocked it at taking 18 times as long as the stock version of Algorithm::Diff for a 4000-line file. It will get worse
       quadratically as array sizes increase.

SYNOPSIS

	 use Algorithm::DiffOld qw(diff LCS traverse_sequences);

	 @lcs	 = LCS( @seq1, @seq2, $comparison_function );

	 $lcsref = LCS( @seq1, @seq2, $comparison_function );

	 @diffs = diff( @seq1, @seq2, $comparison_function );

	 traverse_sequences( @seq1, @seq2,
			    { MATCH => $callback,
			      DISCARD_A => $callback,
			      DISCARD_B => $callback,
			    },
			    $comparison_function );

COMPARISON FUNCTIONS

       Each of the main routines should be passed a comparison function. If you aren't passing one in, use Algorithm::Diff instead.

       These functions should return a true value when two items should compare as equal.

       For instance,

	 @lcs	 = LCS( @seq1, @seq2, sub { my ($a, $b) = @_; $a eq $b } );

       but if that is all you're doing with your comparison function, just use Algorithm::Diff and let it do this (this is its default).

       Or:

	 sub someFunkyComparisonFunction
	 {
	       my ($a, $b) = @_;
	       $a =~ m{$b};
	 }

	 @diffs = diff( @lines, @patterns, &someFunkyComparisonFunction );

       which would allow you to diff an array @lines which consists of text lines with an array @patterns which consists of regular expressions.

       This is actually the reason I wrote this version -- there is no way to do this with a key generation function as in the stock
       Algorithm::Diff.

perl v5.18.2							    2006-07-30						     Algorithm::DiffOld(3)