Question

我正在关注一本非常好的python书，它教你如何为某些纸牌游戏创建模拟。正如您在下面所见，我创建了一个类“卡”，用于索引卡中所有可能的卡组合。然后我创建了一个“Deck”类，它从“Card”中的卡组合制作了套牌。我的问题是，我正在尝试模拟某人从decl中取出一张卡片，但无法使最后一个类函数removeCard工作，我不太清楚为什么。有人可以帮助我理解我的问题以及如何纠正它吗？谢谢。

class Card:
def __init__(self, suit = 0, rank = 2):
    Card.suit = suit
    Card.rank = rank
#Two class attributes that are helpful in determining suit/rank
ranklist = ['narf', 'Ace', 'Two', 'Three', 'Four', 'Five', \
'Six', 'Seven', 'Eight', 'Nine', 'Ten', 'Jack', 'Queen', 'King']
suitlist = ['Clubs', 'Diamonds', 'Hearts', 'Spades']
def __repr__(self):
    return (self.ranklist[self.rank] + " of " + self.suitlist[self.suit])


class Deck:
def __init__(self):
    self.cards = []
    for suit in range(4):
        for rank in range(1,13):
            x = Card()
            x.rank = rank
            x.suit = suit 
            self.cards.append(x)
def printDeck(self):
    for card in self.cards:
        print(card)

def removeCard(self, card):
        if card in self.cards:
            self.cards.remove(card)
            return True
        else:
            return False

Answer 1

首先，您的卡片__init__功能中有拼写错误。您应该将属性分配给self，而不是Card。

其次，我猜你正在做类似的事情：

class Card:
    def __init__(self, suit = 0, rank = 2):
        self.suit = suit
        self.rank = rank
    #Two class attributes that are helpful in determining suit/rank
    ranklist = ['narf', 'Ace', 'Two', 'Three', 'Four', 'Five', \
    'Six', 'Seven', 'Eight', 'Nine', 'Ten', 'Jack', 'Queen', 'King']
    suitlist = ['Clubs', 'Diamonds', 'Hearts', 'Spades']
    def __repr__(self):
        return (self.ranklist[self.rank] + " of " + self.suitlist[self.suit])


class Deck:
    def __init__(self):
        self.cards = []
        for suit in range(4):
            for rank in range(1,13):
                x = Card()
                x.rank = rank
                x.suit = suit 
                self.cards.append(x)
    def printDeck(self):
        for card in self.cards:
            print(card)

    def removeCard(self, card):
            if card in self.cards:
                self.cards.remove(card)
                return True
            else:
                return False

d = Deck()
print "The deck has {} cards.".format(len(d.cards))
card = Card(1,1)
print "Removing the {}.".format(card)
d.removeCard(card)
print "The deck has {} cards.".format(len(d.cards))

您希望输出为：

The deck has 48 cards.
Removing the Ace of Diamonds.
The deck has 47 cards.

但实际上你得到了：

The deck has 48 cards.
Removing the Ace of Diamonds.
The deck has 48 cards.

你的removeCard方法失败了，因为默认情况下，python中的对象只有在它们的id相等时才相等。例如：

>>> a = Card(1,1)
>>> b = Card(1,1)

>>> a == a
True
>>> id(a) == id(a)
True

>>> a == b
False
>>> id(a) == id(b)
False

尽管a和b都是用Card(1,1)创建的，但它们并不相同。当您尝试if card in self.cards:时，Python会问，self.cards是否包含具有此确切ID的卡？对于我的第一个代码段，它会回复False。

您可以在__eq__课程中指定自己的Card来覆盖此默认行为。

class Card:
    def __init__(self, suit = 0, rank = 2):
        self.suit = suit
        self.rank = rank
    #Two class attributes that are helpful in determining suit/rank
    ranklist = ['narf', 'Ace', 'Two', 'Three', 'Four', 'Five', \
    'Six', 'Seven', 'Eight', 'Nine', 'Ten', 'Jack', 'Queen', 'King']
    suitlist = ['Clubs', 'Diamonds', 'Hearts', 'Spades']
    def __eq__(self, other):
        if not isinstance(other, Card): return False
        return self.suit == other.suit and self.rank == other.rank
    def __repr__(self):
        return (self.ranklist[self.rank] + " of " + self.suitlist[self.suit])

现在in和remove的行为正常，并根据需要删除您的卡片。

The deck has 48 cards.
Removing the Ace of Diamonds.
The deck has 47 cards.

纸牌游戏模拟list.remove

1 个答案: