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=head1 NAME |
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String::Similarity - calculate the similarity of two strings |
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=head1 SYNOPSIS |
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use String::Similarity; |
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$similarity = similarity $string1, $string2; |
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$similarity = similarity $string1, $string2, $limit; |
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=head1 DESCRIPTION |
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=over 4 |
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=cut |
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package String::Similarity; |
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use Exporter; |
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use DynaLoader; |
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$VERSION = '1.04'; |
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@ISA = qw/Exporter DynaLoader/; |
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@EXPORT = qw(similarity); |
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@EXPORT_OK = qw(fstrcmp); |
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bootstrap String::Similarity $VERSION; |
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=item $factor = similarity $string1, $string2, [$limit] |
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The C<similarity>-function calculates the similarity index of |
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its two arguments. A value of C<0> means that the strings are |
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entirely different. A value of C<1> means that the strings are |
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identical. Everything else lies between 0 and 1 and describes the amount |
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of similarity between the strings. |
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It roughly works by looking at the smallest number of edits to change one |
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string into the other. |
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You can add an optional argument C<$limit> (default 0) that gives the |
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minimum similarity the two strings must satisfy. C<similarity> stops |
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analyzing the string as soon as the result drops below the given limit, |
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in which case the result will be invalid but lower than the given |
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C<$limit>. You can use this to speed up the common case of searching for |
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the most similar string from a set by specifying the maximum similarity |
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found so far. |
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=cut |
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# out of historical reasons, I prefer "fstrcmp" as the original name. |
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*similarity = *fstrcmp; |
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1; |
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=back |
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=head1 SEE ALSO |
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|
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The basic algorithm is described in: |
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"An O(ND) Difference Algorithm and its Variations", Eugene Myers, |
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Algorithmica Vol. 1 No. 2, 1986, pp. 251-266; |
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see especially section 4.2, which describes the variation used below. |
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The basic algorithm was independently discovered as described in: |
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"Algorithms for Approximate String Matching", E. Ukkonen, |
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Information and Control Vol. 64, 1985, pp. 100-118. |
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=head1 AUTHOR |
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Marc Lehmann <schmorp@schmorp.de> |
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http://home.schmorp.de/ |
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(the underlying fstrcmp function was taken from gnu diffutils and |
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modified by Peter Miller <pmiller@agso.gov.au> and Marc Lehmann |
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<schmorp@schmorp.de>). |
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