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A collection of edit distance algorithms in Ruby.

Includes Levenshtein, Restricted Edit (Optimal Alignment) and Damerau-Levenshtein distances, and Jaro & Jaro-Winkler similarity.


Add this line to your application's Gemfile:

gem 'edits'

And then execute:

$ bundle

Or install it yourself as:

$ gem install edits



Edit distance, accounting for deletion, addition and substitution.

Edits::Levenshtein.distance "raked", "bakers"
# => 3
Edits::Levenshtein.distance "iota", "atom"
# => 4
Edits::Levenshtein.distance "acer", "earn"
# => 4

# Max distance
Edits::Levenshtein.distance_with_max "iota", "atom", 2
# => 2
Edits::Levenshtein.most_similar "atom", %w[tree rota toes racer]
# => "toes"

Restricted Edit (Optimal Alignment)

Edit distance, accounting for deletion, addition, substitution and transposition (two adjacent characters are swapped). This variant is restricted by the condition that no sub-string is edited more than once.

Edits::RestrictedEdit.distance "raked", "bakers"
# => 3
Edits::RestrictedEdit.distance "iota", "atom"
# => 3
Edits::RestrictedEdit.distance "acer", "earn"
# => 4

# Max distance
Edits::RestrictedEdit.distance_with_max "iota", "atom", 2
# => 2
Edits::RestrictedEdit.most_similar "atom", %w[tree rota toes racer]
# => "rota"


Edit distance, accounting for deletions, additions, substitution and transposition (two adjacent characters are swapped).

Edits::DamerauLevenshtein.distance "raked", "bakers"
# => 3
Edits::DamerauLevenshtein.distance "iota", "atom"
# => 3
Edits::DamerauLevenshtein.distance "acer", "earn"
# => 3

Jaro & Jaro-Winkler

Edits::Jaro.similarity "information", "informant"
# => 0.90235690235690236
Edits::Jaro.distance "information", "informant"
# => 0.097643097643097643

Edits::JaroWinkler.similarity "information", "informant"
# => 0.94141414141414137
Edits::JaroWinkler.distance "information", "informant"
# => 0.05858585858585863


After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.


Bug reports and pull requests are welcome on GitHub at https://github.com/tcrouch/edits.


The gem is available as open source under the terms of the MIT License.