Python入门(2.7.8) O'Reilly 视频系列练习

Question

我正在尝试完成O'Reilly's Beginning Python视频系列中的一个练习。我的代码似乎(至少对我来说)从视频中复制示例，但我得到以下错误。

Traceback (most recent call last):
File "blackjack.py", line 20, in <module> print(d.deal())
File "blackjack.py", line 15, in deal return self.cards.pop()
AttributeError: 'deck' object has no attribute 'cards'

下面是我通常使用的代码:

import random
class deck(object):
    def shuffle(self):
        suits = ['Spades','Hearts','Clubs','Diamonds']
        ranks = ['1','2','3','4','5','6','7','8','9','10','J','Q','K','A']
        self.cards = []
        for x in suits:
            for y in ranks:
                self.cards.append(y + x)
        random.shuffle(self.cards)
    def deal(self):
        return self.cards.pop()
d = deck()
d.shuffle
print(d.deal())
print(d.deal())

似乎它与我的self.cards列表变量有关。有人有什么想法吗?

Answer 1

d.shuffle() # is missing  parens

您需要调用method d.shuffle()与父母。

In [3]: d = deck()
In [4]: d.shuffle
Out[4]: <bound method deck.shuffle of <__main__.deck object at 0x7fb8a4a04d10>>
In [5]: print(d.deal())
---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
<ipython-input-5-a5c7b7294801> in <module>()
----> 1 print(d.deal())
<ipython-input-2-0b86145ed058> in deal(self)
     13 
     14     def deal(self):
---> 15         return self.cards.pop()
AttributeError: 'deck' object has no attribute 'cards'
In [6]: d.shuffle()  # call the method
In [7]: print(d.deal()) # now all good
AHearts

Answer 2

您不是在呼叫shuffle()。你需要括号

shuffle()是一个类方法，因为它需要在它的名字后面加上括号。你可以不带括号访问类属性，但是方法必须有它们。