Python3魔术方法实现一摞卡牌

1.纸牌代码实现

import collections

Card = collections.namedtuple('Card', ['rank', 'suit'])


class FrenchDeck:

    # 纸牌点数
    ranks = [str(n) for n in range(2, 11)] + list('JQKA')
    # 纸牌花色
    suits = 'spades diamonds clubs hearts'.split()

    def __init__(self):
        self._cards = [Card(rank, suit) for suit in self.suits for rank in self.ranks]

    def __len__(self):
        return len(self._cards)

    def __getitem__(self, position):
        return self._cards[position]

    得到一个纸牌对象：

beer_card = Card('7', 'diamonds')
print(beer_card)

    FrenchDeck这个类和任何标准Python集合类型一样，可以用len()来查看一叠牌有多少张

deck = FrenchDeck()
print(len(deck))

    还能通过__getitem__方法抽取特定的牌

print(deck[0], deck[-1])

    随机抽牌

from random import choice
print(choice(deck))
print(choice(deck))
print(choice(deck))

    deck类还支持切片

print(deck[:3])
print(deck[12:13])

    这一摞牌还是可迭代的

for card in deck:
    print(card)