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Revision: 1.1
Committed: Sat Jun 25 09:55:53 2005 UTC (19 years ago) by root
Branch: MAIN
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# User Rev Content
1 root 1.1 =head1 NAME
2    
3     String::Similarity - calculate the similarity of two strings
4    
5     =head1 SYNOPSIS
6    
7     use String::Similarity;
8    
9     $similarity = similarity $string1, $string2;
10     $similarity = similarity $string1, $string2, $limit;
11    
12     =head1 DESCRIPTION
13    
14     =over 4
15    
16     =cut
17    
18     package String::Similarity;
19    
20     require DynaLoader;
21    
22     $VERSION = '1.02';
23     @ISA = qw/Exporter DynaLoader/;
24     @EXPORT = qw(similarity);
25     @EXPORT_OK = qw(fstrcmp);
26    
27     bootstrap String::Similarity $VERSION;
28    
29     =item $factor = similarity $string1, $string2, [$limit]
30    
31     The C<similarity>-function calculates the similarity index of
32     its two arguments. A value of C<0> means that the strings are
33     entirely different. A value of C<1> means that the strings are
34     identical. Everything else lies between 0 and 1 and describes the amount
35     of similarity between the strings.
36    
37     It roughly works by looking at the smallest number of edits to change one
38     string into the other.
39    
40     You can add an optional argument C<$limit> (default 0) that gives the
41     minimum similarity the two strings must satisfy. C<similarity> stops
42     analyzing the string as soon as the result drops below the given limit,
43     in which case the result will be invalid but lower than the given
44     C<$limit>. You can use this to speed up the common case of searching for
45     the most similar string from a set by specifing the maximum similarity
46     found so far.
47    
48     =cut
49    
50     # out of historical reasons, I prefer "fstrcmp" as the original name.
51     *similarity = *fstrcmp;
52    
53     1;
54    
55     =back
56    
57     =head1 SEE ALSO
58    
59     The basic algorithm is described in:
60     "An O(ND) Difference Algorithm and its Variations", Eugene Myers,
61     Algorithmica Vol. 1 No. 2, 1986, pp. 251-266;
62     see especially section 4.2, which describes the variation used below.
63    
64     The basic algorithm was independently discovered as described in:
65     "Algorithms for Approximate String Matching", E. Ukkonen,
66     Information and Control Vol. 64, 1985, pp. 100-118.
67    
68     =head1 AUTHOR
69    
70     Marc Lehmann <schmorp@schmorp.de>
71     http://home.schmorp.de/
72    
73     (the underlying fstrcmp function was taken from gnu diffutils and
74     modified by Peter Miller <pmiller@agso.gov.au> and Marc Lehmann
75     <schmorp@schmorp.de>).
76    
77    
78