takes two company names (strings) as an input and returns a similarity index on the scale of 0 to 100.

string_similarity check

# http://www.catalysoft.com/articles/StrikeAMatch.html

class Similarity
	def initialize(str1, str2)
		@str1 = str1
		@str2 = str2
		@set1 = build_character_pair(str1)
		@set2 = build_character_pair(str2)
	end

	def calculate
		intersection = (@set1 & @set2)
		collection = @set1 + @set2

		result = ((2 * intersection.size).to_f / collection.size.to_f) * 100
		return result.round
	end	

	private
	def build_character_pair(str)
		charset = []
		char_array = str.split('')
		char_array.each_with_index do |v, i|
			unless i == char_array.length-1
				charset << "#{v}#{char_array[i+1]}"
			end
		end
		return charset
	end
end


Example:

similarity = Similarity.new("Tata consultancy services", "Tata motors")
similarity.calculate # return the calculated similarity