Module: PgTrgm

Defined in:
lib/pg_trgm.rb,
lib/pg_trgm/version.rb

Constant Summary collapse

VERSION = 
"0.0.1"

Class Method Summary collapse

Class Method Details

.similarity(v1, v2) ⇒ Object

inspired by gist.github.com/komasaru/41b0c93e264be75eabfa



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# File 'lib/pg_trgm.rb', line 20

def self.similarity(v1, v2)
  v1_trigrams = PgTrgm.trigrams v1
  v2_trigrams = PgTrgm.trigrams v2
  return 0 if v1_trigrams.empty? and v2_trigrams.empty?
  count_dup = (v1_trigrams & v2_trigrams).length
  count_all = (v1_trigrams + v2_trigrams).length
  count_dup / count_all.to_f
end

.trigrams(v) ⇒ Object 



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# File 'lib/pg_trgm.rb', line 6

def self.trigrams(v)
  memo = Set.new
  v.to_s.split(/[\W_]+/).each do |word|
    next if word.empty?
    # Each word is considered to have two spaces prefixed and one space suffixed when determining the set of trigrams contained in the string
    word = "  #{word.downcase} "
    word.chars.each_cons(3).map do |cons|
      memo << cons.join
    end
  end
  memo
end