Ruby compare two strings similarity percentage

Question

Id like to compare two strings in Ruby and find their similarity

I\'ve had a look at the Levenshtein gem but it seems this was last updated in 2008 and

Answer 1

I think your question could do with some clarifications, but here's something quick and dirty (calculating as percentage of the longer string as per your clarification above):

def string_difference_percent(a, b)
  longer = [a.size, b.size].max
  same = a.each_char.zip(b.each_char).select { |a,b| a == b }.size
  (longer - same) / a.size.to_f
end

I'm still not sure how much sense this percent difference you are looking for makes, but this should get you started at least.

It's a bit like Levensthein distance, in that it compares the strings character by character. So if two names differ only by the middle name, they'll actually be very different.

Answer 2

There is now a ruby gem for similar_text. https://rubygems.org/gems/similar_text It provides a similar method that compares two strings and returns a number representing the percent similarity between the two strings.

Answer 3

I can recommend the fuzzy-string-match gem.

You can use it like this (taken from the docs):

require "fuzzystringmatch"
jarow = FuzzyStringMatch::JaroWinkler.create(:native)
p jarow.getDistance("jones", "johnson")

It will return a score ~0.832 which tells how good those strings match.