Anagram Detector

anagram.rb

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

  def normalized
    @str.split('?').map do |word|
      # replace all non-alphabet characters with nothing
      word.downcase.gsub(/[^[:alpha:]]/, '')
    end
  end

  def counts
    normalized.map do |word|
      char_counts = {}

      word.chars.each do |char|
        if char_counts[char].nil?
          char_counts[char] = 1
        else
          char_counts[char] += 1
        end
      end

      char_counts
    end
  end

  def is_anagram?
    result =
      if counts.first == counts.last
        'is an anagram of'
      else
        'is NOT an anagram of'
      end

    @str.gsub('?', result)
  end
end

STDIN.readlines.each do |input|
  puts Anagram.new(input).is_anagram?
end