[译] Python 学习 —— __init__() 方法 3

摘要：简单复合对象复合对象也可被称为容器。它难以序列化对象并像这样初始化来重建。接口仍然会导致多种方法计算。还要注意一些不完全遵循点规则的方法功能。逐步增加项目的方法和一步加载所有项目的方法是一样的。另一个方法就是之前那样的类定义。

  
注：原书作者 Steven F. Lott，原书名为 Mastering Object-oriented Python

当我们看到创建Card对象的工厂函数，再看看Card类设计。我想我们可能要重构牌值转换功能，因为这是Card类自身应该负责的内容。这会将初始化向下延伸到每个子类。

这需要共用的超类初始化以及特定的子类初始化。我们要谨遵Don"t Repeat Yourself(DRY)原则来保持代码可以被克隆到每一个子类中。

下面的示例展示了每个子类初始化的职责：

pythonclass Card:
    pass

class NumberCard(Card):
    def  __init__(self, rank, suit):
        self.suit = suit
        self.rank = str(rank)
        self.hard = self.soft = rank

class AceCard(Card):
    def  __init__(self, rank, suit):
        self.suit = suit
        self.rank = "A"
        self.hard, self.soft =  1, 11

class FaceCard(Card):
    def  __init__(self, rank, suit):
        self.suit = suit
        self.rank = {11: "J", 12: "Q", 13: "K"}[rank]
        self.hard = self.soft = 10

pythonclass Card:
    def __init__(self, rank, suit, hard, soft):
        self.rank = rank
        self.suit = suit
        self.hard = hard
        self.soft = soft

class NumberCard(Card):
    def  __init__(self, rank, suit):
        super().__init__(str(rank), suit, rank, rank)

class AceCard(Card):
    def  __init__(self, rank, suit):
        super().__init__("A", suit, 1, 11)

class FaceCard(Card):
    def  __init__(self, rank, suit):
        super().__init__({11: "J", 12: "Q", 13: "K" }[rank], suit, 10, 10)

pythondef card10(rank, suit):
    if rank == 1: 
        return AceCard(rank, suit)
    elif 2 <= rank < 11: 
        return NumberCard(rank, suit)
    elif 11 <= rank < 14: 
        return FaceCard(rank, suit)
    else:
       raise Exception("Rank out of range")

pythond = [card6(r+1, s) for r in range(13) for s in (Club, Diamond, Heart, Spade)]
random.shuffle(d)
hand = [d.pop(), d.pop()]

pythonclass Deck:
    def __init__(self):
        self._cards = [card6(r+1, s) for r in range(13) for s in (Club, Diamond, Heart, Spade)]
        random.shuffle(self._cards)

    def pop(self):
        return self._cards.pop()

pythond = Deck()
hand = [d.pop(), d.pop()]

pythonclass Deck2(list):
    def __init__(self):
        super().__init__(card6(r+1, s) for r in range(13) for s in (Club, Diamond, Heart, Spade))
        random.shuffle(self)

pythonclass Deck3(list):
    def __init__(self, decks=1):
        super().__init__()
        for i in range(decks):
            self.extend(card6(r+1, s) for r in range(13) for s in (Club, Diamond, Heart, Spade))
        random.shuffle(self)
        burn = random.randint(1, 52)
        for i in range(burn): 
            self.pop()

python(card6(r+1, s) for r in range(13) for s in (Club, Diamond, Heart, Spade) for d in range(decks))

pythonclass Hand:
    def __init__(self, dealer_card):
        self.dealer_card = dealer_card
        self.cards = []
    def hard_total(self):
        return sum(c.hard for c in self.cards)
    def soft_total(self):
        return sum(c.soft for c in self.cards)

pythond = Deck()
h = Hand(d.pop())
h.cards.append(d.pop())
h.cards.append(d.pop())

pythonclass Hand2:
   def __init__(self, dealer_card, *cards):
       self.dealer_card = dealer_card
       self.cards = list(cards)
   def hard_total(self):
       return sum(c.hard for c in self.cards)
   def soft_total(self):
       return sum(c.soft for c in self.cards)

pythond = Deck()
P = Hand2(d.pop())
p.cards.append(d.pop())
p.cards.append(d.pop())

pythond = Deck()
h = Hand2(d.pop(), d.pop(), d.pop())