Anagram count

gistfile1.rb

# Given a list of words, return a hash with the anagram counting

class String
  # Returns the associated anagram (string with the same letters sorted)
  # Ex: "accb".anagram # => "abcc"
  def anagram
    split('').sort.join
  end
end

class Hash
  # Returns a new hash with the same keys but the count of values in each value as value
  # Ex: {:a => [1,2,3], :b => 'x'}.to_values_count  # => {:a => 3, :b => 1}
  def to_values_count
    inject({}) do |result, key_value_pair|
      result.merge!(key_value_pair.first => Array(key_value_pair.last).size)
    end
  end

  # Bang version of to_values_count
  def to_values_count!
    each {|k, v| merge!(k => Array(v).size)}
  end
end

words = %w(abb bba aba bba abb aab abc bab)

words.group_by(&:anagram).to_values_count # => {"abb" => 5, "aab" => 2, "abc" => 1}