== amatch - Approximate Matching Extension for Ruby

=== Description

This is a collection of classes that can be used for Approximate
matching, searching, and comparing of Strings. They implement algorithms
that compute the Levenshtein edit distance, Sellers edit distance, the
Hamming distance, the longest common subsequence length, the longest common
substring length, the pair distance metric, the Jaro-Winkler metric.

=== Download

The latest version of <b>amatch</b> can be found at

* http://rubyforge.org/frs/?group_id=390

Online Documentation should be located at

* http://amatch.rubyforge.org

=== Installation

Just type into the command line as root:

 # ruby install.rb

If you have installed rake (rake.rubyforge.org), you can also type:

 # rake install

To install this extension as a gem type

 # gem install amatch

=== Examples
 require 'amatch'
 # => true
 include Amatch
 # => Object
 
 m = Sellers.new("pattern")
 # => #<Amatch::Sellers:0x40366324>
 m.match("pattren")
 # => 2.0
 m.substitution = m.insertion = 3
 # => 3
 m.match("pattren")
 # => 4.0
 m.reset_weights
 # => #<Amatch::Sellers:0x40366324>
 m.match(["pattren","parent"])
 # => [2.0, 4.0]
 m.search("abcpattrendef")
 # => 2.0
 
 m = Levenshtein.new("pattern")
 # => #<Amatch::Levenshtein:0x4035919c>
 m.match("pattren")
 # => 2
 m.search("abcpattrendef")
 # => 2
 "pattern language".levenshtein_similar("language of patterns")
 # => 0.2
 
 m = Hamming.new("pattern")
 # => #<Amatch::Hamming:0x40350858>
 m.match("pattren")
 # => 2
 "pattern language".hamming_similar("language of patterns")
 # => 0.1
 
 m = PairDistance.new("pattern")
 # => #<Amatch::PairDistance:0x40349be8>
 m.match("pattr en")
 # => 0.545454545454545
 m.match("pattr en", nil)
 # => 0.461538461538462
 m.match("pattr en", /t+/)
 # => 0.285714285714286
 "pattern language".pair_distance_similar("language of patterns")
 # => 0.928571428571429
 
 m = LongestSubsequence.new("pattern")
 # => #<Amatch::LongestSubsequence:0x4033e900>
 m.match("pattren")
 # => 6
 "pattern language".longest_subsequence_similar("language of patterns")
 # => 0.4
 
 m = LongestSubstring.new("pattern")
 # => #<Amatch::LongestSubstring:0x403378d0>
 m.match("pattren")
 # => 4
 "pattern language".longest_substring_similar("language of patterns")
 # => 0.4

 m = Jaro.new("pattern")
 # => #<Amatch::Jaro:0x363b70>
 m.match("paTTren")
 # => 0.952380952380952
 m.ignore_case = false
 m.match("paTTren")
 # => 0.742857142857143
 "pattern language".jaro_similar("language of patterns")
 # => 0.672222222222222

 m = JaroWinkler.new("pattern")
 # #<Amatch::JaroWinkler:0x3530b8>
 m.match("paTTren")
 # => 0.971428571712403
 m.ignore_case = false
 m.match("paTTren")
 # => 0.79428571505206
 m.scaling_factor = 0.05
 m.match("pattren")
 # => 0.961904762046678
 "pattern language".jarowinkler_similar("language of patterns")
 # => 0.672222222222222

=== Author

Florian Frank mailto:flori@ping.de

=== License

This is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License Version 2 as published by
the Free Software Foundation: http://www.gnu.org/copyleft/gpl.html