From: Dave Burt <dave@...>
Date: 2005-03-23T22:19:49+09:00
Subject: Re: [SOLUTION][QUIZ] Texas Hold'Em (#24)

I apologise for posting the URL incorrectly. It's really:
http://www.dave.burt.id.au/ruby/poker.rb

This is a pretty long project. Here are some highlights:

# each hand type has a name and a function taking a hand and returning it,
# sorted, or nil if the hand doesn't match this type.
 HandTypes = [
  ['Royal Flush', proc {|hand|
   if hand.find_all{|c|c.value >= 10}.map(:suit).frequencies(5).size >= 1
    Poker.find_straight(hand)
   end }],
  ['Straight Flush', proc {|hand|
   suit, count = *hand.map(:suit).frequencies(5)[0]
   if count && count >= 1
    if straight = Poker.find_straight(hand.find_all {|card| card.suit == 
suit })
     result = hand.dup
     result.delete_if {|card| straight.include?(card) }
     straight + result.sort_by_most_frequent(:value)
    end
   end }],
  ['Four of a Kind', proc {|hand|
   if hand.map(:value).frequencies(2).size >= 4
    hand.sort_by_most_frequent :value
   end }],
  ['Flush', proc {|hand|
   if hand.map(:suit).frequencies(5).size >= 1
    hand.sort_by_most_frequent :suit
   end }],
  ['Straight', proc {|hand|
   Poker.find_straight(hand) }],
  ['Three of a Kind', proc {|hand|
   if hand.map(:value).frequencies(3).size >= 1
    hand.sort_by_most_frequent :value
   end }],
  ['Two Pair', proc {|hand|
   if hand.map(:value).frequencies(2).size >= 2
    hand.sort_by_most_frequent :value
   end }],
  ['Pair', proc {|hand|
   if hand.map(:value).frequencies(2).size >= 1
    hand.sort_by_most_frequent :value
   end }],
  ['High Card', proc {|hand|
   hand.sort.reverse }]
 ]

 #
 # Returns [n, "Hand type", ordered_cards]
 # The n at the front is bigger for better hands, so that
 # you can sort by hand_value.
 #
 def self.hand_value(cards, min_cards = 7)   #  self #=> Poker:Module
  if cards.size >= min_cards
   HandTypes.each_with_index do |hand_type, index|
    hand_match = hand_type[1].call(cards)
    if hand_match
     # return EvaluatedHand.new(hand_match, hand_type[0], [HandTypes.size - 
index, hand_match])
     return [
      HandTypes.size - index,
      hand_type[0],
      hand_match
     ]
    end
   end
  end
  [0, '', cards.sort_by_most_frequent(:value)]
 end

# then it all comes together like this:

 hands = []

 # get hands from input and evaluate them
 input.each do |line|
  hands << line.to_cards.poker_value
 end

 # determine the winner
 winner = hands.inject([]) do |memo, hand|
  [memo, hand].max
 end

 # output each hand and its value
 hands.each do |hand|
  puts "#{hand[2]} #{hand[1]} #{'(winner)' if hand == winner}"
 end

That plus a Poker::find_straight and Array#frequencies and that's pretty 
much all there is to my answer.

Cheers,
Dave

"Dave Burt" <dave@burt.id.au> faked:
> http://www.dave.burt.id.au/poker.rb
>
> (requires card.rb in the same directory)
>
> An explanation (and comments) will come later tonight.
>
> Cheers,
> Dave