How to check array for range in Ruby?

Question

I am writing a poker program and I can’t understand how to handle the straight.

Straight: all cards in a hand of 5 cards are consecutive values. ex. 2..6, 3..7, 4..8, 5..9, 6..T, 7..J, 8..Q, 9..K, T..A

cards = [2, 3, 4, 5, 6, 7, 8, 9, "T", "J", "Q", "K", "A"]

How can I check a hand, which is an array, for these combinations? Preferably, I can check it to see if it is 5 in a row in the map array.

Answer 1

Edit 2: This is my final decision:

require 'set'
STRAIGHTS = ['A',*2..9,'T','J','Q','K','A'].each_cons(5).map(&:to_set)
  #=> [#<Set: {"A", 2, 3, 4, 5}>, #<Set: {2, 3, 4, 5, 6}>,
  #   ...#<Set: {9, "T", "J", "Q", "K"}>, #<Set: {"T", "J", "Q", "K", "A"}>]

def straight?(hand)
  STRAIGHTS.include?(hand.to_set)
end

STRAIGHTS.include?([6,3,4,5,2].to_set)
  # STRAIGHTS.include?(#<Set: {6, 3, 4, 5, 2}>)
  #=> true 

straight?([6,5,4,3,2])            #=> true 
straight?(["T","J","Q","K","A"])  #=> true 
straight?(["A","K","Q","J","T"])  #=> true
straight?([2,3,4,5,"A"])          #=> true 

straight?([6,7,8,9,"J"])          #=> false 
straight?(["J",7,8,9,"T"])        #=> false 

1: @mudasobwa , , 'A',2,3,4,5 . , . ( , , 'K','A',2,3,4 .)

:

CARDS     = [2, 3, 4, 5, 6, 7, 8, 9, "T", "J", "Q", "K", "A"]
STRAIGHTS = CARDS.each_cons(5).to_a
  #=>[[2, 3, 4, 5, 6], [3, 4, 5, 6, 7], [4, 5, 6, 7, 8],
  #   [5, 6, 7, 8, 9], [6, 7, 8, 9, "T"], [7, 8, 9, "T", "J"],
  #   [8, 9, "T", "J", "Q"], [9, "T", "J", "Q", "K"],
  #   ["T", "J", "Q", "K", "A"]] 

def straight?(hand)
  (hand.map {|c| CARDS.index(c)}.sort == [0,1,2,3,12]) ||
  STRAIGHTS.include?(hand.sort {|a,b| CARDS.index(a) <=> CARDS.index(b)})
end

Answer 2

(9 9, "T" 10, "J" 11 ..), , , :

• 4

:

CARD_VALUES = {
    2 =>  2,    3 =>  3,    4 =>  4,
    5 =>  5,    6 =>  6,    7 =>  7,
    8 =>  8,    9 =>  9,  "T" => 10,
  "J" => 11,  "Q" => 12,  "K" => 13,
  "A" => 14
}

def is_straight?(hand)
  hand_sorted = hand.map {|card| CARD_VALUES[card] }
    .sort.uniq

  hand_sorted.size == 5 &&
    (hand_sorted.last - hand_sorted.first) == 4
end

(1) map, (2) sort , (3) uniq. :

    hand |  4   A   T   A   2 |  2   2   3   3   4 |  5   6   4   8   7 |  3  6  2  8  7
---------+--------------------+--------------------+--------------------+----------------
 1. map  |  4  14  10  14   2 |  2   2   3   3   4 |  5   6   4   8   7 |  3  6  2  8  7
 2. sort |  2   4  10  14  14 |  2   2   3   3   4 |  4   5   6   7   8 |  2  3  6  7  8
 3. uniq |  2   4  10  14     |  2   3   4         |  4   5   6   7   8 |  2  3  6  7  8

...

, , :

, . Enumerable#each_cons, .

CARDS = [ 2, 3, 4, 5, 6, 7, 8, 9, "T", "J", "Q", "K", "A" ]
hand = [ 4, 5, 6, 7, 8 ]

def is_straight?(hand)
  CARDS.each_cons(5).any? do |straight|
    hand == straight
  end
end

if is_straight?(hand)
  puts "Straight!"
else
  puts "Not straight!"
end
# => Straight!

each_cons(5) 5 , hand [ 2, 3, 4, 5, 6 ], [ 3, 4, 5, 6, 7 ], [ 4, 5, 6, 7, 8 ], , any? true.

, , , .

, . - , ( ), sort_by:

def sort_hand(hand)
  hand.sort_by {|card| CARD_VALUES[card] }
end

hand = [ 4, "A", 2, "A", "T" ]
sort_hand(hand)
# => [ 2, 4, "T", "A", "A" ]

Answer 3

:

valid_hands = cards[0..8].each_with_index.map{|b,i| cards[i..i+4]}
#=> [[2, 3, 4, 5, 6], [3, 4, 5, 6, 7], [4, 5, 6, 7, 8], [5, 6, 7, 8, 9], [6, 7, 8, 9, "T"], [7, 8, 9, "T", "J"], [8, 9, "T", "J", "Q"], [9, "T", "J", "Q", "K"], ["T", "J", "Q", "K", "A"]]

, , , ​​ ? () :

if valid_hands.any? { |h| (h - hand).empty? } 
   puts "Valid hand"
else
   puts "Not Valid"
end

UPDATE

2, 3, 4, 5, "A", 2, 3, 4, "K", "A", 2, 3, "Q", "K", "A", 2, "J", "Q", "K", "A" , :

valid_hands = cards.each_with_index.map { |b,i| i < 9 ? cards[i..i+4] : cards[0..i-9] + cards[i..-1] }
# => [[2, 3, 4, 5, 6], [3, 4, 5, 6, 7], [4, 5, 6, 7, 8], [5, 6, 7, 8, 9], [6, 7, 8, 9, "T"], [7, 8, 9, "T", "J"], [8, 9, "T", "J", "Q"], [9, "T", "J", "Q", "K"], ["T", "J", "Q", "K", "A"], [2, "J", "Q", "K", "A"], [2, 3, "Q", "K", "A"], [2, 3, 4, "K", "A"], [2, 3, 4, 5, "A"]]

Answer 4

, , .

hand = [2, 5, 7, 'A', 'J'].map(&:to_s)

'23456789TJQKA' =~ hand.sort_by{|hc| '23456789TJQKA'.index(hc)}.join ||
   'A23456789TJQK' =~ hand.sort_by{|hc| 'A23456789TJQK'.index(hc)}.join

:

suit = '23456789TJQKA'

suit =~ hand.sort_by{|hc| suit.index(hc)}.join ||
   suit.rotate(-1) =~ hand.sort_by{|hc| suit.rotate(-1).index(hc)}.join

Answer 5

(, , ). :

deck = Deck.new.shuffle!
hand = Hand.new(deck.draw 5)
hand.straight?
#=>false
puts hand
8♣ 8♦ T♠ 2♦ 7♦

(.. )

, . .

class Card
  include Enumerable #enables sorting
  attr_accessor :value, :suit

  @values = [2, 3, 4, 5, 6, 7, 8, 9, "T", "J", "Q", "K", "A"]
  @suits  = ["♣","♦","♥","♠"]

  def self.all
    @values.product(@suits).map{|c| Card.new c}
  end

  def self.straight?(cards)
    ["A", *@values].each_cons(5).include?(cards.map(&:value))
  end

  def self.flush?(cards)
    cards.map(&:suit).uniq.size == 1
  end

  def initialize(v)
    @value, @suit = *v
  end

  def <=>(other) #for sorting
    @values.index(value) <=> @values.index(other.value)
  end

  def to_s
    "#{value}#{suit}"
  end
end

deck = Card.all
puts deck
#=> 2♣ 2♦ 2♥ 2♠ 3♣ 3♦ 3♥ 3♠ 4♣ 4♦ 4♥ 4♠ 5♣ 5♦ 5♥ 5♠ 6♣ 6♦ 6♥ 6♠ 7♣ 7♦ 7♥ 7♠ 8♣ 8♦ 8♥ 8♠ 9♣ 9♦ 9♥ 9♠ T♣ T♦ T♥ T♠ J♣ J♦ J♥ J♠ Q♣ Q♦ Q♥ Q♠ K♣ K♦ K♥ K♠ A♣ A♦ A♥ A♠
hand = deck.sample 5
puts hand
#=> Q♥ 6♦ 2♣ T♠ Q♦
Card.straight?(hand)
#=>false

Answer 6

0:

class CardUtils
end

1: Hash

Hash .

@@card_values = {
    'A' => 1,   2  => 2,   3  => 3, 4 => 4,  5 => 5,
     6  => 6,   7  => 7,   8  => 8, 9 => 9, 'T' => 10,
    'J' => 11, 'Q' => 12, 'K' => 13
}

, , .

@@card_values['A']
# => 1

@@card_values[8]
# => 8

2:

sort! .

def self.sort(hand)
    hand.sort {|x,y| @@card_values[x] <=> @@card_values[y]}
end
#  => ["A", 2, 3, 4, 5, 6, 7, 8, 9, "T", "J", "Q", "K"] 

3: , ,

def self.is_consecutive(x, y)
    val_x = @@card_values[x]
    val_y = @@card_values[y]

    val_x == val_y - 1 || val_x + 13 == val_y
end
# is_consecutive('A', 2)
#  => true
# is_consecutive('K', 'A')
#  => true
# is_consecutive('A', 3)
#  => false

4: ""

.

def self.has_straight(hand)
    hand = sort(hand)

    max_consecutive_count = 0
    consecutive_count = 0

    hand.each_with_index do |curr, i|
        prev = hand[i - 1]

        if is_consecutive(prev, curr) then
            consecutive_count += 1
        else
            consecutive_count = 0
        end

        if consecutive_count > max_consecutive_count then
            max_consecutive_count = consecutive_count
        end
    end

    max_consecutive_count >= 5
end
# hand = [2, 3, 4, 5, 6, 7, 8, 9, "T", "J", "Q", "K", "A"]
# CardUtils.has_straight(hand)
#  => true

class CardUtils
    @@card_values = {
        'A' => 1,   2  => 2,   3  => 3, 4 => 4,  5 => 5,
         6  => 6,   7  => 7,   8  => 8, 9 => 9, 'T' => 10,
        'J' => 11, 'Q' => 12, 'K' => 13
    }

    def self.is_consecutive(x, y)
        val_x = @@card_values[x]
        val_y = @@card_values[y]

        val_x == val_y - 1 || val_x + 13 == val_y
    end

    def self.sort(hand)
        hand.sort {|x,y| @@card_values[x] <=> @@card_values[y]}
    end

    def self.has_straight(hand)
        hand = sort(hand)

        max_consecutive_count = 0
        consecutive_count = 0

        hand.each_with_index do |curr, i|
            prev = hand[i - 1]

            if is_consecutive(prev, curr) then
                consecutive_count += 1
            else
                consecutive_count = 0
            end

            if consecutive_count > max_consecutive_count then
                max_consecutive_count = consecutive_count
            end
        end

        max_consecutive_count >= 5
    end
end

Answer 7

:

hand  = [3,4,5,2,'A']


def is_straight(hand)

  # No need to check further if we do not have 5 unique cards.
  return false unless hand.uniq.size == 5

  # Note the A at beginning AND end to count A as 1 or 14.
  list_of_straights = 'A23456789TJQKA'.chars.each_cons(5)

  sorted_hand = hand.map(&:to_s).sort

  list_of_straights.any? do |straight| 
    straight.sort==sorted_hand
  end

end

puts is_straight(hand) #=> true  

, , :

  hand_as_stings = hand.map(&:to_s)

  list_of_straights.any? do |straight| 
    (straight-hand_as_stings).empty?
  end