sexta-feira, maio 31, 2013

Advanced Python Class: "Blackjack"



Game Specification:


"Phase one


Download the program template for this mini-project and review the class definition for the Card class. This class is already implemented so your task is to familiarize yourself with the code. Start by pasting the Card class definition into the provided testing template and verifying that our implementation works as expected.

Implement the methods __init__, __str__, add_card for the Hand class. We suggest modeling a hand as a list of cards.

For help in implementing the __str__ method for hands, refer back to practice exercise number four from last week.

Remember to use the string method for cards to convert each card object into a string. Once you have implemented the Hand class, test it using the provided testing template.

Implement the methods for the Deck class listed in the mini-project template. We suggest modeling a deck of cards as list of cards. You can generate this list using a pair of nested for loops or a list comprehension.

Remember to use the Card initializer to create your cards.

Use random.shuffle() to shuffle this deck of cards. Once you have implemented the Deck class, test your Deck class using the provided testing template.

mplement the handler for a "Deal" button that shuffles the deck and deals the two cards to both the dealer and the player. The event handler deal for this button should shuffle the deck (stored as a global variable), create new player and dealer hands (stored as global variables), and add two cards to each hand. To transfer a card from the deck to a hand, you should use the deal_card method of the Deck class and the add_card method of Hand class in combination.The resulting hands should be printed to the console with an appropriate message indicating which hand is which.

Implement the get_value method for the Hand class. You should use the provided VALUE dictionary to look up the value of a single card in conjunction with the logic explained in the video lecture for this project to compute the value of a hand.

Once you have implemented the get_value method, test it using the provided testing template .

Remember that the deck is randomized after shuffling, so the output of the testing template should match the output in the comments in form but not in exact value.

Implement the handler for a "Hit" button. If the value of the hand is less than or equal to 21, clicking this button adds an extra card to player's hand. If the value exceeds 21 after being hit, print "You have busted".

Implement the handler for a "Stand" button. If the player has busted, remind the player that they have busted. Otherwise, repeatedly hit the dealer until his hand has value 17 or more (using a while loop). If the dealer busts, let the player know.

Otherwise, compare the value of the player's and dealer's hands.

If the value of the player's hand is less than or equal to the dealer's hand, the dealer wins. Otherwise the player has won.

Remember the dealer wins ties in our version.

With this design, the player needs to explicitly press "Deal" to start a new deal. This choice will make using the canvas to build an image-based version of Blackjack easier. At this point, we would suggest testing your implementation of Blackjack extensively.

Phase two


In the second phase of your implementation, you will add five features:

Implement your own draw method for the Hand class using the draw method of the Card class. We suggest drawing a hand as a horizontal sequence of cards where the parameter pos is the position of the upper left corner of the leftmost card. To simplify your code, you may assume that only the first five cards of a player's hand need to be visible on the canvas.

Replace printing in the console by drawing text messages on the canvas. We suggest adding a global outcome string that is drawn in the draw handler using draw_text. These messages should prompt the player to take some require action and have a form similar to "Hit or stand?" and "New deal?".

Also, draw the title of the game, "Blackjack", somewhere on the canvas.

Add logic using the global variable in_play that keeps track of whether the player's hand is still being played. If the round is still in play, you should draw an image of the back of a card (provided in the template) over the dealer's first (hole) card to hide it. Once the round is over, the dealer's
hole card should be displayed.

Add a score counter that keeps track of wins and losses for your Blackjack session. In the simplest case (see our demo), the program displays wins minus losses. However, you are welcome to implement a more sophisticated betting/scoring system.

Modify the logic for the "Deal" button to create and shufflea new deck (or restock and shuffle an existing deck) each time the "Deal" button is clicked. This change avoids the situation where the deck becomes empty during play.

Finally, modify the deal function such that, if the "Deal" button is clicked during the middle of a round, the program reports that the player lost the round and updates the score
appropriately.
"

Theoretical Approach:


The most important stuff regarding this game's engine, was the way I had to internalize the card tiles. My own theoretical approach was (taken from my class notes):


This card structure was represented by the following 3 classes ("card", "hand" and "deck"):

# define card class
class Card:
    def __init__(self, suit, rank):
        if (suit in SUITS) and (rank in RANKS):
            self.suit = suit
            self.rank = rank
        else:
            self.suit = None
            self.rank = None
            print "Invalid card: ", suit, rank

    def __str__(self):
        return self.suit + self.rank

    def get_suit(self):
        return self.suit

    def get_rank(self):
        return self.rank

    def draw(self, canvas, pos):
        card_loc = (CARD_CENTER[0] + CARD_SIZE[0] * RANKS.index(self.rank), 
                    CARD_CENTER[1] + CARD_SIZE[1] * SUITS.index(self.suit))
        canvas.draw_image(card_images, card_loc, CARD_SIZE, [pos[0] + CARD_CENTER[0], pos[1] + CARD_CENTER[1]], CARD_SIZE)
        
# define hand class
class Hand:
    def __init__(self):
        self.hand = []
        self.rank1 = []
        self.suit1 = []
        self.position = []
        self.hundred = 0
        self.count = -1

    def __str__(self):
        s = ""
        i = 0
        while i in range(0, len(self.hand)):
            s += (str(self.hand[i]) + " ")
            i += 1
        return s

    def add_card(self, card):
        self.hundred += 100
        self.position.append(self.hundred)
        self.rank1.append(card.get_rank())
        self.suit1.append(card.get_suit())
        self.hand.append(card.get_suit() + card.get_rank())

    # count aces as 1, if the hand has an ace, then add 10 to hand value if it doesn't bust
    def get_value(self):
        self.value = 0
        for i in range(0, len(self.rank1)):
            if (self.rank1[i] == 'A' and self.value <= 10):
                self.value += 11
            else:
                self.value += VALUES.get(self.rank1[i])
        return self.value

    def draw(self, canvas, p, r, s):
        card_location = (CARD_CENTER[0] + CARD_SIZE[0] * RANKS.index(r), 
                    CARD_CENTER[1] + CARD_SIZE[1] * SUITS.index(s))
        canvas.draw_image(card_images, card_location, CARD_SIZE, [p[0] + CARD_CENTER[0], p[1] + CARD_CENTER[1]], CARD_SIZE)  
    
    def drawback(self, canvas, p):
        card_location1 = (CARD_BACK_CENTER[0], CARD_BACK_CENTER[1])
        canvas.draw_image(card_back, card_location1, CARD_BACK_SIZE, [p[0] + CARD_BACK_CENTER[0], p[1] + CARD_BACK_CENTER[1]], CARD_BACK_SIZE)


# define deck class
class Deck:
    def __init__(self):
        self.choice = -1
        del self.deck
        self.deck = []
        for i in range(1, 14):
            j = str(i)
            if (j == '1'):
                self.deck.append(Card('C', 'A').get_suit() + " " + Card('C', 'A').get_rank())
                self.deck.append(Card('S', 'A').get_suit() + " " + Card('C', 'A').get_rank())
                self.deck.append(Card('H', 'A').get_suit() + " " + Card('C', 'A').get_rank())
                self.deck.append(Card('D', 'A').get_suit() + " " + Card('C', 'A').get_rank())
            elif (j == '10'):
                self.deck.append(Card('C', 'T').get_suit() + " " + Card('C', 'T').get_rank())
                self.deck.append(Card('S', 'T').get_suit() + " " + Card('C', 'T').get_rank())
                self.deck.append(Card('H', 'T').get_suit() + " " + Card('C', 'T').get_rank())
                self.deck.append(Card('D', 'T').get_suit() + " " + Card('C', 'T').get_rank())
            elif (j == '11'):
                self.deck.append(Card('C', 'J').get_suit() + " " + Card('C', 'J').get_rank())
                self.deck.append(Card('S', 'J').get_suit() + " " + Card('C', 'J').get_rank())
                self.deck.append(Card('H', 'J').get_suit() + " " + Card('C', 'J').get_rank())
                self.deck.append(Card('D', 'J').get_suit() + " " + Card('C', 'J').get_rank())
            elif (j == '12'):
                self.deck.append(Card('C', 'Q').get_suit() + " " + Card('C', 'Q').get_rank())
                self.deck.append(Card('S', 'Q').get_suit() + " " + Card('C', 'Q').get_rank())
                self.deck.append(Card('H', 'Q').get_suit() + " " + Card('C', 'Q').get_rank())
                self.deck.append(Card('D', 'Q').get_suit() + " " + Card('C', 'Q').get_rank())
            elif (j == '13'):
                self.deck.append(Card('C', 'K').get_suit() + " " + Card('C', 'K').get_rank())
                self.deck.append(Card('S', 'K').get_suit() + " " + Card('C', 'K').get_rank())
                self.deck.append(Card('H', 'K').get_suit() + " " + Card('C', 'K').get_rank())
                self.deck.append(Card('D', 'K').get_suit() + " " + Card('C', 'K').get_rank())
            else:
                self.deck.append(Card('C', j).get_suit() + " " + Card('C', j).get_rank())
                self.deck.append(Card('S', j).get_suit() + " " + Card('C', j).get_rank())
                self.deck.append(Card('H', j).get_suit() + " " + Card('C', j).get_rank())
                self.deck.append(Card('D', j).get_suit() + 

The rest of the Python program I implemented is your run-of-the-mill source code, i.e., nothing new under the sun ...

NB: The source code is available here. This link can also be used to play the game.

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