《流畅的python》：python风格的纸牌

import collections
from random import choice
Card = collections.namedtuple('Card',['rank','suit'])

class FrenchDeck:
    ranks = [str(n) for n in range(2,11)] + list('JQKA')
    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]

代码说明：

1、首先用collections.namedtuple构建了一个类来表示纸牌，文档：https://docs.python.org/zh-cn/3/library/collections.html#collections.namedtuple

这样的类特点：可以通过字段名、索引获取字段值

2、FrenchDeck类实现了特殊方法__len__，__getitem__，将对象的len(),[]操作转到对cards属性的操作

3、实现了__getitem__方法，对象将变成可以迭代

测试代码如下：

   deck = FrenchDeck()
    print(deck)
    print(deck._cards)
    print(len(deck))
    print(choice(deck))
    print(deck[0])
    print(deck[1])
    print(deck[12::13])

    # for card in deck:
    #     print(card)
    #
    #反向迭代
    for card in reversed(deck):
        print(card)

测试结果如下

对扑克牌进行排序：2最小，A最大；同时加上花色的判定；花色值为0-51

def spades_high(card):
    suit_values = dict(spades=3,hearts=2,diamonds=1,clubs=0)
    rank_value = FrenchDeck.ranks.index(card.rank)

    res = rank_value * len(suit_values) + suit_values[card.suit]
    return res

if __name__ == '__main__':
    deck = FrenchDeck()
    print(sorted(deck,key=spades_high))