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Revision: 1.3
Committed: Fri Nov 16 22:55:05 2012 UTC (11 years, 7 months ago) by root
Branch: MAIN
CVS Tags: HEAD
Changes since 1.2: +1 -1 lines
Log Message:
Fabrizio Regalli

File Contents

# Content
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 use Exporter;
21 use DynaLoader;
22
23 $VERSION = '1.04';
24 @ISA = qw/Exporter DynaLoader/;
25 @EXPORT = qw(similarity);
26 @EXPORT_OK = qw(fstrcmp);
27
28 bootstrap String::Similarity $VERSION;
29
30 =item $factor = similarity $string1, $string2, [$limit]
31
32 The C<similarity>-function calculates the similarity index of
33 its two arguments. A value of C<0> means that the strings are
34 entirely different. A value of C<1> means that the strings are
35 identical. Everything else lies between 0 and 1 and describes the amount
36 of similarity between the strings.
37
38 It roughly works by looking at the smallest number of edits to change one
39 string into the other.
40
41 You can add an optional argument C<$limit> (default 0) that gives the
42 minimum similarity the two strings must satisfy. C<similarity> stops
43 analyzing the string as soon as the result drops below the given limit,
44 in which case the result will be invalid but lower than the given
45 C<$limit>. You can use this to speed up the common case of searching for
46 the most similar string from a set by specifying the maximum similarity
47 found so far.
48
49 =cut
50
51 # out of historical reasons, I prefer "fstrcmp" as the original name.
52 *similarity = *fstrcmp;
53
54 1;
55
56 =back
57
58 =head1 SEE ALSO
59
60 The basic algorithm is described in:
61 "An O(ND) Difference Algorithm and its Variations", Eugene Myers,
62 Algorithmica Vol. 1 No. 2, 1986, pp. 251-266;
63 see especially section 4.2, which describes the variation used below.
64
65 The basic algorithm was independently discovered as described in:
66 "Algorithms for Approximate String Matching", E. Ukkonen,
67 Information and Control Vol. 64, 1985, pp. 100-118.
68
69 =head1 AUTHOR
70
71 Marc Lehmann <schmorp@schmorp.de>
72 http://home.schmorp.de/
73
74 (the underlying fstrcmp function was taken from gnu diffutils and
75 modified by Peter Miller <pmiller@agso.gov.au> and Marc Lehmann
76 <schmorp@schmorp.de>).
77
78
79