jellyfish is a library of functions for approximate and phonetic matching of strings.
Source code is availableonGitHub
The library provides implementations of the following algorithms:
PhoneticEncoding
These algorithms convert a string to a normalized phonetic encoding, converting a word to a
representation of its pronunciation. Each takes a single string and returns a coded representation.
AmericanSoundexsoundex(s)
Calculate the American Soundex of the string s.
Soundex is an algorithm to convert a word (typically a name) to a four digit code in the form 'A123'
where 'A' is the first letter of the name and the digits represent similar sounds.
For example soundex('Ann')==soundex('Anne')=='A500' and soundex('Rupert')==soundex('Robert')=='R163'.
See the SoundexarticleatWikipedia for more details.
Metaphonemetaphone(s)
Calculate the metaphone code for the string s.
The metaphone algorithm was designed as an improvement on Soundex. It transforms a word into a string
consisting of '0BFHJKLMNPRSTWXY' where '0' is pronounced 'th' and 'X' is a '[sc]h' sound.
For example metaphone('Klumpz')==metaphone('Clumps')=='KLMPS'.
See the MetaphonearticleatWikipedia for more details.
NYSIISnysiis(s)
Calculate the NYSIIS code for the string s.
The NYSIIS algorithm is an algorithm developed by the New York State Identification and Intelligence
System. It transforms a word into a phonetic code. Like soundex and metaphone it is primarily intended
for use on names (as they would be pronounced in English).
For example nysiis('John')==nysiis('Jan')==JAN.
See the NYSIISarticleatWikipedia for more details.
MatchRatingApproach(codex)match_rating_codex(s)
Calculate the match rating approach value (also called PNI) for the string s.
The Match rating approach algorithm is an algorithm for determining whether or not two names are
pronounced similarly. The algorithm consists of an encoding function (similar to soundex or nysiis)
which is implemented here as well as match_rating_comparison() which does the actual comparison.
See the MatchRatingApproacharticleatWikipedia for more details.
StemmingPorterStemmerporter_stem(s)
Reduce the string s to its stem using the common Porter stemmer.
Stemming is the process of reducing a word to its root form, for example 'stemmed' to 'stem'.
Martin Porter's algorithm is a common algorithm used for stemming that works for many purposes.
See the officialhomepageforthePorterStemmingAlgorithm for more details.
StringComparison
These methods are all measures of the difference (aka editdistance) between two strings.
LevenshteinDistancelevenshtein_distance(s1,s2)
Compute the Levenshtein distance between s1 and s2.
Levenshtein distance represents the number of insertions, deletions, and substitutions required to change
one word to another.
For example: levenshtein_distance('berne','born')==2 representing the transformation of the first e to
o and the deletion of the second e.
See the LevenshteindistancearticleatWikipedia for more details.
Damerau-LevenshteinDistancedamerau_levenshtein_distance(s1,s2)
Compute the Damerau-Levenshtein distance between s1 and s2.
A modification of Levenshtein distance, Damerau-Levenshtein distance counts transpositions (such as ifsh
for fish) as a single edit.
Where levenshtein_distance('fish','ifsh')==2 as it would require a deletion and an insertion, though
damerau_levenshtein_distance('fish','ifsh')==1 as this counts as a transposition.
See the Damerau-LevenshteindistancearticleatWikipedia for more details.
HammingDistancehamming_distance(s1,s2)
Compute the Hamming distance between s1 and s2.
Hamming distance is the measure of the number of characters that differ between two strings.
Typically Hamming distance is undefined when strings are of different length, but this implementation
considers extra characters as differing. For example hamming_distance('abc','abcd')==1.
See the HammingdistancearticleatWikipedia for more details.
JaroSimilarityjaro_similarity(s1,s2)
Compute the Jaro similarity between s1 and s2.
Jaro distance is a string-edit distance that gives a floating point response in [0,1] where 0 represents
two completely dissimilar strings and 1 represents identical strings.
WARNING:
Prior to 0.8.1 this function was named jaro_distance. That name is still available, but is no longer
recommended. It will be replaced in 1.0 with a correct version.
Jaro-WinklerSimilarityjaro_winkler_similarity(s1,s2)
Compute the Jaro-Winkler distance between s1 and s2.
Jaro-Winkler is a modification/improvement to Jaro distance, like Jaro it gives a floating point response
in [0,1] where 0 represents two completely dissimilar strings and 1 represents identical strings.
WARNING:
Prior to 0.8.1 this function was named jaro_winkler. That name is still available, but is no longer
recommended. It will be replaced in 1.0 with a correct version.
See the Jaro-WinklerdistancearticleatWikipedia for more details.
MatchRatingApproach(comparison)match_rating_comparison(s1,s2)
Compare s1 and s2 using the match rating approach algorithm, returns True if strings are
considered equivalent or False if not. Can also return None if s1 and s2 are not comparable
(length differs by more than 3).
The Match rating approach algorithm is an algorithm for determining whether or not two names are
pronounced similarly. Strings are first encoded using match_rating_codex() then compared according to
the MRA algorithm.
See the MatchRatingApproacharticleatWikipedia for more details.
Changelog0.8.9-26October2021
• fix buffer overflow in NYSIIS
• remove unnecessary/undocumented special casing of digits in Jaro-Winkler
0.8.8-17August2021
• release fix to fix Linux wheel issue
0.8.7-16August2021
• safer allocations from CJellyfish
• include aarch64 wheels
0.8.4-4August2021
• fix for jaro winkler (cjellyfish#8)
0.8.3-11March2021
• build changes
• include OSX and Windows wheels
0.8.2-21May2020
• fix jaro_winkler/jaro_winkler_similarity mix-up
• deprecate jaro_distance in favor of jaro_similarity backwards compatible shim left in place, will be
removed in 1.0
• (note: 0.8.1 was a broken release without proper C libraries)
0.8.0-21May2020
• rename jaro_winkler to jaro_winkler_similarity to match other functions backwards compatible shim
added, but will be removed in 1.0
• fix soundex bug with W/H cases, #83
• fix metaphone bug with WH prefix, #108
• fix C match rating codex bug with duplicate letters, #121
• fix metaphone bug with leading vowels and 'kn' pair, #123
• fix Python jaro_winkler bug #124
• fix Python 3.9 deprecation warning
• add manylinux wheels
0.7.2-5June2019
• fix CJellyfish damerau_levenshtein w/ unicode, thanks to immerrr
• fix final H in NYSIIS
• fix issue w/ trailing W in metaphone
0.7.1-10January2019
• restrict install to Python >= 3.4
0.7.0-10January2019
• drop Python 2 compatibility & legacy code
• add bugfix for NYSIIS for words starting with PF
0.6.1-April162018
• fixed wheel release issue
0.6.0-April72018
• fix quite a few bugs & differences between C/Py implementations
• add wagner-fischer testdata
• uppercase soundex result
• better error handling in nysiis, soundex, and jaro
0.5.6-June232016
• bugfix for metaphone & soundex raising unexpected TypeErrors on Windows (#54)
0.5.5-June212016
• bugfix for metaphone WH case
0.5.4-May132016
• bugfix for C version of damerau_levenshtein thanks to Tyler Sellon
0.5.3-March152016
• style/packaging changes
0.5.2-February32016
• testing fixes for Python 3.5
• bugfix for Metaphone w/ silent H thanks to Jeremy Carbaugh
0.5.1-July122015
• bugfixes for NYSIIS
• bugfixes for metaphone
• bugfix for C version of jaro_winkler
0.5.0-April232015
• consistent unicode behavior, all functions take unicode and reject bytes on Py2 and 3, C and Python
• parametrize tests
• Windows compiler support
0.4.0-March272015
• tons of new tests
• documentation
• split out cjellyfish
• test all w/ unicode and plenty of fixes to accommodate
• 100% test coverage
0.3.4-February42015
• fix segfaults and memory leaks via Danrich Parrol
0.3.3-November202014
• fix bugs in damerau and NYSIIS
0.3.2-August112014
• fix for jaro-winkler from David McKean
• more packaging fixes
0.3.1-July162014
• packaging fix for C/Python alternative
0.3.0-July152014
• python alternatives where C isn't available
0.2.2-March142014
• testing fixes
• assorted bugfixes in NYSIIS
0.2.0-January262012
• incorporate some speed changes from Peter Scott
• segfault bugfixes.
0.1.2-September162010
• initial working release
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