How can you find all anagrams for one word?

Question

I'm trying to get all the anagrams for one word with Ruby but my code doesn't work, I only get three results for the string 'ant'. Any help would be much appreciated.

class Anagram
    attr_reader :word
  def initialize(word)
    @word = word.downcase
  end

  def anagram_maker
    @word_bank = []
    index = @word.length
    minus_one = index - 1

    while (index * minus_one) != 0
      anagram = @word.split('').shuffle.join
      @word_bank << anagram
      index -= 1
    end
    @word_bank = @word_bank.uniq
  end

  def display
    anagram_maker
    if @word_bank.count > 1
      @word_bank.each do |anagram|
        puts anagram
      end
    else
      puts "Not enough letters for an anagram"
    end
  end

end

Not sure what else to try here.

Answer 1

Your code is quite un-idiomatic Ruby.

Computing anagrams of a string is a matter of computing the permutations of the characters of the string, and Ruby makes this task quite easy. An example reproducing your Anagram class is:

class Anagram
  def initialize(word)
    @word = word
  end

  def display        
    # In Ruby 2.0 @word.chars will return an array, no need for `to_a`.
    @word.chars.to_a.permutation.map(&:join).uniq.each do |anagram|
      puts anagram
    end
  end
end

anagram = Anagram.new('ant')
anagram.display

# Output
# ant
# atn
# nat
# nta
# tan
# tna

To answer your question: you get only three anagrams because the while loop inside the anagram_maker method is executed three times (the length of the string). Moreover I guess that just shuffling characters is not the proper way of generating permutations, see "Algorithm to generate anagrams" for more information about implementing an anagram algorithm.

Answer 2

Also if you wanted a revision of your own code so that you can learn in context of your own writing style you could try this:

class Anagram
    attr_reader :word, :combinations
  def initialize(word)
    @word = word.downcase
    @combinations = ([email protected]).inject(:*)
  end

  def anagram_maker
    @word_bank = []
    index = @word.length
    minus_one = index - 1

    while @word_bank.uniq.count < @combinations
      anagram = @word.split('').shuffle.join
      @word_bank << anagram
    end
    @word_bank = @word_bank.uniq
  end

  def display
    anagram_maker
    if @word_bank.count > 1
      @word_bank.each do |anagram|
        puts anagram
      end
    else
      puts "Not enough letters for an anagram"
    end
  end
end

This is far less efficient than the aforementioned but relevant none-the-less.