poker.rb

module Poker
  class Card
    attr_accessor :number, :mark

    def initialize(number, mark)
      @number = number
      @mark = mark
    end

    def number_string
      case @number
      when 1
        "A"
      when 11
        "J"
      when 12
        "Q"
      when 13
        "K"
      else
        @number
      end
    end

    def mark_string
      case @mark
      when :spade
        "♠"
      when :heart
        "♥"
      when :diamond
        "♦"
      when :club
        "♣"
      end
    end

    def to_s
      "#{mark_string} #{number_string}"
    end
  end

  class Hand
    def initialize
      @cards = [
        Card.new(1, :spade),
        Card.new(2, :heart),
        Card.new(3, :diamond),
        Card.new(3, :heart),
        Card.new(2, :club),
      ]
    end

    def to_s
      @cards.map {|card| card.to_s }.join(",")
    end

    def rank
      count = 0
      @cards.each do |left|
        @cards.each do |top|
          count += 1 if left.number == top.number
        end
      end
      count
    end
  end
end

hand = Poker::Hand.new
puts hand
puts hand.rank

途中すぎる感じのコードですが、rubygems.org に poker gem があったので作るのやめた