Module: English::Soundex

Defined in:
lib/gems/english-0.3.1/lib/english/soundex.rb

Overview

Ruby implementation of the Soundex algorithm, as described by Knuth in volume 3 of The Art of Computer Programming.

Class Method Summary collapse

Class Method Details

.soundex(str) ⇒ Object

Returns nil if the value couldn’t be calculated b/c of empty-string or invalid character.

"Ruby".soundex  #=> "R100"



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# File 'lib/gems/english-0.3.1/lib/english/soundex.rb', line 27

def soundex(str)
  return nil if str.empty?

  str = str.upcase
  last_code = soundex_code(str[0,1])
  soundex_code = str[0,1]

  for index in 1...(str.size) do
    return soundex_code if soundex_code.size == 4

    code = soundex_code(str[index,1])

    if code == "0" then
      last_code = nil
    elsif code == nil then
      return nil
    elsif code != last_code then
      soundex_code += code
      last_code = code
    end
  end

  return soundex_code + "000"[0,4-soundex_code.size]
end

.soundex_code(char) ⇒ Object

Support function for String#soundex. Returns code for a single character.



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# File 'lib/gems/english-0.3.1/lib/english/soundex.rb', line 55

def soundex_code(char)
  char.tr! "AEIOUYWHBPFVCSKGJQXZDTLMNR", "00000000111122222222334556"
end