anagram.rb

class AnagramTest < MiniTest::Unit::TestCase

  class Anagram
    def initialize(word)
      @word = word
      # If you create the array here, then the results will be
      # collected over multiple calls to `match`. Not sure if that is
      # intended or not, so I'll assume it's ok to change.
    end

    def match(candidates)
      # This never changes during the loop, so I'd extract it. Could
      # maybe even be in the constructor.
      matching_letters = letters(@word)

      # Almost any time you have the pattern `create collection;
      # manipulate collection; return collection`, there's a
      # functional replacement.
      anagrams = candidates.select do |candidate|
        # The inside of blocks is usually indented
        letters(candidate) == matching_letters
        # I prefer to do exactly one thing when processing arrays, I
        # find it's easier to follow in the future.
      end

      # I like using the array / set operators. Here I just want to
      # make sure the results never have the original word. This also
      # removes a conditional.
      anagrams - [@word]
    end

    # Extract a little helper, just to make sure we are always doing
    # the same to both sides.
    def letters(word)
      # Not sure that we need the join here.
      word.to_s.downcase.chars.sort
      # The to_s is a good call! That way you are sure you have a string.
    end
    private :letters
  end
end