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# File 'lib/philiprehberger/fuzzy_match/dice.rb', line 6
def self.coefficient(str_a, str_b)
a = str_a.to_s.downcase
b = str_b.to_s.downcase
return 1.0 if a == b
return 0.0 if a.length < 2 || b.length < 2
bigrams_a = bigrams(a)
bigrams_b = bigrams(b)
intersection = 0
b_copy = bigrams_b.dup
bigrams_a.each do |bg|
idx = b_copy.index(bg)
if idx
intersection += 1
b_copy.delete_at(idx)
end
end
(2.0 * intersection) / (bigrams_a.length + bigrams_b.length)
end
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