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NAME |
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String::Similarity - calculate the similarity of two strings |
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SYNOPSIS |
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use String::Similarity; |
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$similarity = similarity $string1, $string2; |
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$similarity = similarity $string1, $string2, $limit; |
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DESCRIPTION |
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$factor = similarity $string1, $string2, [$limit] |
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The "similarity"-function calculates the similarity index of its two |
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arguments. A value of 0 means that the strings are entirely |
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different. A value of 1 means that the strings are identical. |
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Everything else lies between 0 and 1 and describes the amount of |
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similarity between the strings. |
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It roughly works by looking at the smallest number of edits to |
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change one string into the other. |
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You can add an optional argument $limit (default 0) that gives the |
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minimum similarity the two strings must satisfy. "similarity" stops |
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analyzing the string as soon as the result drops below the given |
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limit, in which case the result will be invalid but lower than the |
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given $limit. You can use this to speed up the common case of |
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searching for the most similar string from a set by specifing the |
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maximum similarity found so far. |
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SEE ALSO |
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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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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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