Vladlev

An implementation of the levenshtein distance algorithm for ruby using FFI

Add this line to your gemfile and then run bundle to install

gem 'vladlev'

Vladlev will calculate the levenshtein distance between two strings. The levenshtein distance is the number of transforms necessary to transform one string to be idential to the other. A transform is defined as an addition, deletion, or alteration of a single character in a string.

In order to calculate the distance

Vladlev.distance("string1", "string2")
>> 1

Vladlev also includes a 3 parameter version of the distance method. The third parameter is "maximum distance", which tells Vladlev to stop calculation once the distance becomes greater than this parameter.

In order to use this optimization

Vladlev.distance("string1234567890", "string1", 1)
>> 16

Vladlev.distance("string1234567890", "string1", 999)
>> 9

When given a pair of strings such that the distance between the two strings is greater than the "maximum distance" paramter, Vladlev will return the length of the longest string rather than spend the effort of calculating the distance when you know that you are not interested in the result.

Vladlev uses rake-compiler for a build tool

bundle exec rake compile

bundle exec rake clean

For an agressive clean of compiled files, you can do this

bundle exec rake clobber