如何使用 Python 以人类可读的方式打印卡片组

Question

I am creating a deck of cards as a list and need to print out the deck. However, when I try to print the deck, it returns the object ID rather than something readable.

Note, the code here is incomplete. The Deck class should take in an input suit and return the cards 2, 3, 4, 5, 6, 7, 8, 9, 10, J, Q, K, A for that suit. The default should return a full 52 card deck. However, I haven't figured out a way to make the default all of the suits yet. Currently the default is saved as spades as a placeholder.

I have tried using str and repr functions, but it doesn't seem to make a difference. I am also not getting an error from my attempted implementation of repr function, so I assume that I am not messing up the syntax or anything.

from random import shuffle

# possible errors
class Error(Exception):
   """Base class for other exceptions"""
   pass
class RankError(Error):
    """Raised when input rank is not a valid card rank"""
    pass
class SuitError(Error):
   """Raised when input rank is not a valid card suit"""
   pass
class NoCardsError(Error):
    """Raised when deck does not have enough cards to deal"""
    pass

all_rank = ["2", "3", "4", "5", "6", "7", "8", "9", "10", "J", "Q", "K", "A"]
all_suit = ["♠", "♥", "♦", "♣"] 
hand = []

class PlayingCard:
    def __init__(self, rank, suit):
        if str(rank) not in all_rank:
            raise RankError("Invalid rank! Rank must be 2, 3, 4, 5, 6, 7, 8, 9, 10, J, Q, K, or A")
        if suit not in all_suit:
            raise SuitError("Invalid suit! Suit must be ♠, ♥, ♦, or ♣")
        self.rank = rank
        self.suit = suit
    def __str__(self):
        return str(self.rank) + " of " + str(self.suit)

class Deck:
    def __init__(self, suit = "♠"): # current default is spades, need to think of way to make default all the suits
        self.cards = [PlayingCard(rank, suit) for rank in all_rank]

    def __repr__(self):
        return "%r of %r" % (self.rank, self.suit)

    def shuffle_deck():
        self.shuffled_cards = random.shuffle(self.cards)

    def deal_card(card_count):
        if card_count > len(cards):
            raise NoCardsError("Not enough cards in the deck to deal.")
        else:
            hand = hand.append(cards.pop())
            return hand


deck1 = Deck()
print(deck1.cards)

I expect a list output that looks like

[2 of ♠, 3 of ♠, 4 of ♠, 5 of ♠, 6 of ♠, etc.]

but the actual output is

[< main .PlayingCard object at 0x000001BE6C17EDD8>, < main .PlayingCard object at 0x000001BE6C17EB38>, < main .PlayingCard object at 0x000001BE6C17E748>, < main .PlayingCard object at 0x000001BE6C17E198>, < main .PlayingCard object at 0x000001BE6C17E400>, < main .PlayingCard object at 0x000001BE6C17E6A0>, < main .PlayingCard object at 0x000001BE6C17EE80>, < main .PlayingCard object at 0x000001BE6C17E470>, < main .PlayingCard object at 0x000001BE6C17E320>, < main .PlayingCard object at 0x000001BE6C17EEB8>, < main .PlayingCard object at 0x000001BE6C17E160>, < main .PlayingCard object at 0x000001BE6C17E358>, < main .PlayingCard ZA8CFDE6331BD59EB2AC96F8911C4B6 66Z at 0x000001BE6C17EF98>]

Answer 1

To print uncover the weird object notation, try putting the __repr__ definition in the PlayingCard class

For example:

class PlayingCard:
    def __init__(self, rank, suit):
        if str(rank) not in all_rank:
            raise RankError("Invalid rank! Rank must be 2, 3, 4, 5, 6, 7, 8, 9, 10, J, Q, K, or A")
        if suit not in all_suit:
            raise SuitError("Invalid suit! Suit must be ♠, ♥, ♦, or ♣")
        self.rank = rank
        self.suit = suit
    def __str__(self):
        return str(self.rank) + " of " + str(self.suit)

    # ADDITION HERE
    def __repr__(self):
        return "%r of %r" % (self.rank, self.suit)

So running print(deck1.cards) will output

['2' of '♠', '3' of '♠', '4' of '♠', '5' of '♠', '6' of '♠', '7' of '♠', '8' of '♠', '9' of '♠', '10' of '♠', 'J' of '♠', 'Q' of '♠', 'K' of '♠', 'A' of '♠']

To print the entire deck , you'll need to update the __init__ definition for the Deck class.

def __init__(self, suit = all_suit):
    self.cards = [PlayingCard(rank, one_suit) for rank in all_rank
                                              for one_suit in suit]

Running print(deck1.cards) again, it'll print out the following.

['2' of '♠', '2' of '♥', '2' of '♦', '2' of '♣', '3' of '♠', '3' of '♥', '3' of '♦', '3' of '♣', '4' of '♠', '4' of '♥', '4' of '♦', '4' of '♣', '5' of '♠', '5' of '♥', '5' of '♦', '5' of '♣', '6' of '♠', '6' of '♥', '6' of '♦', '6' of '♣', '7' of '♠', '7' of '♥', '7' of '♦', '7' of '♣', '8' of '♠', '8' of '♥', '8' of '♦', '8' of '♣', '9' of '♠', '9' of '♥', '9' of '♦', '9' of '♣', '10' of '♠', '10' of '♥', '10' of '♦', '10' of '♣', 'J' of '♠', 'J' of '♥', 'J' of '♦', 'J' of '♣', 'Q' of '♠', 'Q' of '♥', 'Q' of '♦', 'Q' of '♣', 'K' of '♠', 'K' of '♥', 'K' of '♦', 'K' of '♣', 'A' of '♠', 'A' of '♥', 'A' of '♦', 'A' of '♣']

And to double check how many we have:

print(len(deck1.cards))  # 52