Dwi Wahyudi

Senior Software Engineer (Ruby, Golang, Java)

2 Weeks ago, I wanted to have some fun writing Ruby code. It was about calculating values of hands in Holdem Poker.

Overview

https://en.wikipedia.org/wiki/Texas_hold_%27em

Royal Flush, Straight Flush, Four of a Kind, etc. You got the idea.

Card Model

So the first step is to model the card itself.

class Card
  attr_accessor :suit, :rank, :value

  def initialize(suit, rank, value)
    @suit = suit
    @rank = rank
    @value = value
  end

  def to_s
    "#{rank}#{suit}"
  end
end
  • Suit is clover, diamond, heart, and spade, with symbols: ♣ ♦ ♥ ♠.
  • Rank is A (ace), 2, 3, 4 … J, Q and K.
  • Value is value for this card, this is a bit tricky for ace.

Cards Generator

Next, I want to generate a pack of card, with all of those 4 suits and 13 ranks. In total there will be 52 card, each with unique pair of suit and rank.

require_relative 'card'

class CardsGenerator
  SUITS = %w[♣ ♦ ♥ ♠]
  RANKS = {
    "A" => 1,
    "2" => 2,
    "3" => 3,
    "4" => 4,
    "5" => 5,
    "6" => 6,
    "7" => 7,
    "8" => 8,
    "9" => 9,
    "10" => 10,
    "J" => 11,
    "Q" => 12,
    "K" => 13
  }

  def perform
    cards = []
    SUITS.each do |suit|
      RANKS.each do |rank, value|
        card = Card.new
        card.suit = suit
        card.rank = rank
        card.value = value

        cards << card
      end
    end

    cards
  end
end

On next part we will try to create a deck of shuffled cards.