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fuzzy: Fuzzy string matching and phonetics in SQLite

The sqlean-fuzzy extension provides fuzzy-matching helpers:

  • Measure distance between two strings.
  • Compute phonetic string code.
  • Transliterate a string.

If you want a ready-to-use mechanism to search a large vocabulary for close matches, see the spellfix extension instead.

String distances • Phonetic codes • Transliteration • Acknowledgements • Installation and usage

String distances

These functions measure the distance between two strings.

Only ASCII strings are supported. Use the translit function to convert the input string from UTF-8 to plain ASCII.

damlev • editdist • hamming • jarowin • leven • osadist

fuzzy_damlev

fuzzy_damlev(x, y)

Calculates the Damerau-Levenshtein distance.

select fuzzy_damlev('awesome', 'aewsme');
-- 2

fuzzy_editdist

fuzzy_editdist(x, y)

Calculates the spellcheck edit distance.

select fuzzy_editdist('awesome', 'aewsme');
-- 215

fuzzy_hamming

fuzzy_hamming(x, y)

Calculates the Hamming distance.

select fuzzy_hamming('awesome', 'aewsome');
-- 2

fuzzy_jarowin

fuzzy_jarowin(x, y)

Calculates the Jaro-Winkler distance.

select fuzzy_jarowin('awesome', 'aewsme');
-- 0.907142857142857

fuzzy_leven

Calculates the Levenshtein distance.

select fuzzy_leven('awesome', 'aewsme');
-- 3

fuzzy_osadist

fuzzy_osadist(x, y)

Calculates the Optimal String Alignment distance.

select fuzzy_osadist('awesome', 'aewsme');
-- 3

Phonetic codes

These functions compute phonetic string codes.

Only ASCII strings are supported. Use the translit function to convert the input string from UTF-8 to plain ASCII.

caver • phonetic • soundex • rsoundex

fuzzy_caver

fuzzy_caver(x)

Calculates the Caverphone code.

select fuzzy_caver('awesome');
-- AWSM111111

fuzzy_phonetic

fuzzy_phonetic(x)

Calsulates the spellcheck phonetic code.

select fuzzy_phonetic('awesome');
-- ABACAMA

fuzzy_soundex

fuzzy_soundex(x)

Calculates the Soundex code.

select fuzzy_soundex('awesome');
-- A250

fuzzy_rsoundex

fuzzy_rsoundex(x)

Calculates the Refined Soundex code.

select fuzzy_rsoundex('awesome');
-- A03080

Transliteration

fuzzy_translit(str)

Transliteration converts the input string from UTF-8 into plain ASCII by converting all non-ASCII characters to some combination of characters in the ASCII subset.

The distance and phonetic functions are ASCII only, so to work with a Unicode string, you should first transliterate it:

select fuzzy_translit('sí señor');
-- si senor

select fuzzy_translit('привет');
-- privet

Some characters may be lost:

select fuzzy_translit('oh my 😅');
-- oh my ?

Acknowledgements

Adapted from libstrcmp by Ross Bayer and spellfix.c by D. Richard Hipp.

Installation and usage

SQLite command-line interface:

sqlite> .load ./fuzzy
sqlite> select fuzzy_soundex('hello');

See How to install an extension for usage with IDE, Python, etc.

↓ Download the extension.

⛱ Explore other extensions.

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