Approximate String Matching library
C Ruby
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Latest commit 351285f Jul 4, 2017

README.md

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.

Installation

To install this extension as a gem type

gem install amatch

into the shell.

Download

The homepage of this library is located at

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 = Amatch::DamerauLevenshtein.new("pattern")
# => #<Amatch::DamerauLevenshtein:0x007fc3483dd278>
m.match("pattren")
# => 1
"pattern language".damerau_levenshtein_similar("language of patterns")
# => 0.19999999999999996

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

Apache License, Version 2.0 – See the COPYING file in the source archive.