一、abstractmethod

• 子類必須全部實現重寫父類的abstractmethod方法
• 非abstractmethod方法可以不實現重寫
• 帶abstractmethod方法的類不能實例化

  from abc import abstractmethod, ABCMeta

 1 class BettingStrategy(metaclass=ABCMeta):
 2 
 3     @abstractmethod
 4     def bet(self):
 5         print(‘0‘)
 6 
 7     def record_win(self):
 8         print
 
(‘win‘)
 9 
10     def record_loss(self):
11         print(‘loss‘)
12 
13 
14 class Bet(BettingStrategy):
15     def bet(self):
16         print(‘1‘)

擴展：abc模塊

二、staticmethod：靜態函數

對象不用實例化即可調用的函數

 1 class Hand4:
 2     def __init__(self, dealer_card, *cards):
 3         self.dealer_card = dealer_card
 
 4         self.cards = cards
 5 
 6     @staticmethod
 7     def freeze(other):
 8         hand = Hand4(other.dealer_card, *other.cards)
 9         return hand
10 
11     @staticmethod
12     def split(other, card0, card1):
13         hand0 = Hand4(other.dealer_card, other.cards[0], card0)
14         hand1 = Hand4(other.dealer_card, other.cards[1], card1)
 
15         return hand0, hand1
16 
17     def __str__(self):
18         return ‘,‘.join(map(str, self.cards))

1 h41 = Hand4(deck3.pop(), deck3.pop(), deck3.pop())
2     s1, s2 = Hand4.split(h41, deck3.pop(), deck3.pop())
3     s3 = Hand4.freeze(h41)

Python面向對象編程——一些類定義（雜）