这篇教程python接口,继承,重载运算符详解写得很实用，希望能帮到您。
1. 序列__getitem__如果没有 __iter__ 和 __contains__ 方法，
Python 会调用 __getitem__ 方法，
设法让 迭代 和 in 运算符可用
class Foo: def __getitem__(self, pos): return range(0, 30, 10)[pos]f = Foo()print(f[1]) # 10for i in f: print(i) # 0, 10, 20# 如果没有 __iter__ 和 __contains__ 方法，# Python 会调用 __getitem__ 方法，# 设法让迭代和 in 运算符可用
2. __setitem__import collectionsCard = 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] def __str__(self): return ",".join(str(i) for i in self._cards)from random import shuffledeck = FrenchDeck()print(str(deck))# Card(rank='2', suit='spades'),Card(rank='3', suit='spades'),Card(rank='4', suit='spades'),Card(rank='5', suit='spades'),Card(rank='6', suit='spades'),Card(rank='7', suit='spades'),Card(rank='8', suit='spades'),Card(rank='9', suit='spades'),Card(rank='10', suit='spades'),Card(rank='J', suit='spades'),Card(rank='Q', suit='spades'),Card(rank='K', suit='spades'),Card(rank='A', suit='spades'),Card(rank='2', suit='diamonds'),Card(rank='3', suit='diamonds'),Card(rank='4', suit='diamonds'),Card(rank='5', suit='diamonds'),Card(rank='6', suit='diamonds'),Card(rank='7', suit='diamonds'),Card(rank='8', suit='diamonds'),Card(rank='9', suit='diamonds'),Card(rank='10', suit='diamonds'),Card(rank='J', suit='diamonds'),Card(rank='Q', suit='diamonds'),Card(rank='K', suit='diamonds'),Card(rank='A', suit='diamonds'),Card(rank='2', suit='clubs'),Card(rank='3', suit='clubs'),Card(rank='4', suit='clubs'),Card(rank='5', suit='clubs'),Card(rank='6', suit='clubs'),Card(rank='7', suit='clubs'),Card(rank='8', suit='clubs'),Card(rank='9', suit='clubs'),Card(rank='10', suit='clubs'),Card(rank='J', suit='clubs'),Card(rank='Q', suit='clubs'),Card(rank='K', suit='clubs'),Card(rank='A', suit='clubs'),Card(rank='2', suit='hearts'),Card(rank='3', suit='hearts'),Card(rank='4', suit='hearts'),Card(rank='5', suit='hearts'),Card(rank='6', suit='hearts'),Card(rank='7', suit='hearts'),Card(rank='8', suit='hearts'),Card(rank='9', suit='hearts'),Card(rank='10', suit='hearts'),Card(rank='J', suit='hearts'),Card(rank='Q', suit='hearts'),Card(rank='K', suit='hearts'),Card(rank='A', suit='hearts')shuffle(deck) # TypeError: 'FrenchDeck' object does not support item assignment加入__setitem__ def __setitem__(self, key, value): self._cards[key] = value shuffle(deck) print(str(deck))# 牌被随机打乱了# Card(rank='6', suit='hearts'),Card(rank='2', suit='spades'),Card(rank='3', suit='hearts'),Card(rank='A', suit='clubs'),Card(rank='7', suit='clubs'),Card(rank='Q', suit='diamonds'),Card(rank='5', suit='hearts'),Card(rank='6', suit='spades'),Card(rank='5', suit='diamonds'),Card(rank='8', suit='diamonds'),Card(rank='K', suit='hearts'),Card(rank='Q', suit='hearts'),Card(rank='8', suit='hearts'),Card(rank='3', suit='diamonds'),Card(rank='Q', suit='clubs'),Card(rank='A', suit='diamonds'),Card(rank='9', suit='hearts'),Card(rank='7', suit='diamonds'),Card(rank='A', suit='spades'),Card(rank='J', suit='hearts'),Card(rank='3', suit='clubs'),Card(rank='4', suit='hearts'),Card(rank='Q', suit='spades'),Card(rank='10', suit='diamonds'),Card(rank='10', suit='hearts'),Card(rank='K', suit='diamonds'),Card(rank='2', suit='diamonds'),Card(rank='4', suit='spades'),Card(rank='3', suit='spades'),Card(rank='7', suit='hearts'),Card(rank='9', suit='clubs'),Card(rank='J', suit='clubs'),Card(rank='J', suit='diamonds'),Card(rank='10', suit='spades'),Card(rank='4', suit='diamonds'),Card(rank='7', suit='spades'),Card(rank='9', suit='diamonds'),Card(rank='2', suit='hearts'),Card(rank='6', suit='clubs'),Card(rank='K', suit='clubs'),Card(rank='4', suit='clubs'),Card(rank='A', suit='hearts'),Card(rank='K', suit='spades'),Card(rank='2', suit='clubs'),Card(rank='J', suit='spades'),Card(rank='8', suit='spades'),Card(rank='5', suit='spades'),Card(rank='9', suit='spades'),Card(rank='10', suit='clubs'),Card(rank='8', suit='clubs'),Card(rank='6', suit='diamonds'),Card(rank='5', suit='clubs') 或者 在类外打补丁 FrenchDeck.__setitem__ = 函数 def set_card(deck, position, card): deck._cards[position] = cardFrenchDeck.__setitem__ = set_card
3. 抽象基类class Test: def __len__(self): return 24from collections import abcprint(isinstance(Test(), abc.Sized)) # True 只要实现了 __len__() 方法，就可以被 abc.Sized 识别为子类
4. 不要直接子类化内置类型class AnswerDict(dict): def __getitem__(self, key): return 24ad = AnswerDict(a="good")print(ad['a']) # 24d = {}d.update(ad)print(d['a']) # goodprint(ad) # {'a': 'good'}print(d) # {'a': 'good'}直接子类化内置类型（如 dict、list 或 str）容易出错， 因为 内置类型的方法 通常会 忽略用户覆盖的方法。
不要子类化内置 类型，用户自己定义的类 应该继承 collections 模块 中的类，例如 UserDict、UserList 和 UserString，这些类做了特殊设计，因 此易于扩展
5. 继承顺序import collectionsclass AnswerDict2(collections.UserDict): def __getitem__(self, key): return 24ad = AnswerDict2(a="good")print(ad['a']) # 24d = {}d.update(ad)print(d['a']) # 24print(ad) # {'a': 'good'}print(d) # {'a': 24} - 多重继承的同名方法调用，根据类的 __mro__ 属性顺次在类中查找
- 推荐使用 super() 函数
6. 重载运算符
不可变类型，，一定不能实现就地特殊方法
__iadd__等增量赋值特殊方法 必须返回 self
总结本篇文章就到这里了，希望能给你带来帮助，也希望您能够多多关注51zixue.net的更多内容！
在前女友婚礼上用python把婚礼现场的WIFI名称改成了
手把手带你了解python多进程,多线程 |
