getitems setitems delitmes
dic = {'k':'v'}
# 对象 ： 存储属性 和调用方法
dic['k'] = 'v'
class Foo:def __init__(self,name,age,sex):self.name = nameself.age = ageself.sex = sexdef __getitem__(self, item):if hasattr(self,item):return self.__dict__[item]def __setitem__(self, key, value):self.__dict__[key] = valuedef __delitem__(self, key):del self.__dict__[key]f = Foo('egon',38,'男')
print(f['name'])
f['hobby'] = '男'
print(f.hobby,f['hobby'])
del f.hobby # object 原生支持 __delattr__
del f['hobby'] # 通过自己实现的
print(f.__dict__)
new
# 设计模式
# 23种
# 单例模式
# 一个类 始终 只有 一个 实例
# 当你第一次实例化这个类的时候 # __init__ 初始化方法
# __new__ 构造方法 : 创建一个对象
class A:def __init__(self):self.x = 1print('in init function')def __new__(cls, *args, **kwargs):print('in new function')return object.__new__(A, *args, **kwargs)a1 = A()
a2 = A()
a3 = A()print(a1)就创建一个实例化的对象
# 当你之后再来实例化的时候 就用之前创建的对象class A:__instance = Falsedef __init__(self,name,age):self.name = nameself.age = agedef __new__(cls, *args, **kwargs):if cls.__instance:return cls.__instancecls.__instance = object.__new__(cls)return cls.__instanceegon = A('egg',38)
egon.cloth = '小花袄'
nezha = A('nazha',25)
print(nezha)
print(egon)
print(nezha.name)
print(egon.name)
print(nezha.cloth)hash
hash() #__hash__
class A:def __init__(self,name,sex):self.name = nameself.sex = sexdef __hash__(self):return hash(self.name+self.sex)a = A('egon','男')
b = A('egon','nv')
print(hash(a))
print(hash(b))
eq
class A:def __init__(self,name):self.name = namedef __eq__(self, other):if self.__dict__ == other.__dict__:return Trueelse:return Falseob1 = A('egon')
ob2 = A('egg')
print(ob1 == ob2)案例import json
from collections import namedtuple
Card = namedtuple('Card',['rank','suit']) # rank 牌面的大小 suit牌面的花色
class FranchDeck:ranks = [str(n) for n in range(2,11)] + list('JQKA') # 2-Asuits = ['红心','方板','梅花','黑桃']def __init__(self):self._cards = [Card(rank,suit) for rank in FranchDeck.ranksfor suit in FranchDeck.suits]def __len__(self):return len(self._cards)def __getitem__(self, item):return self._cards[item]def __setitem__(self, key, value):self._cards[key] = valuedef __str__(self):return json.dumps(self._cards,ensure_ascii=False)deck = FranchDeck()
print(deck[10])
from random import choice
print(choice(deck)) #随机抽取
# print(choice(deck))
from random import shuffle
shuffle(deck)#洗牌
print(deck[10])
print(deck)
print(deck[:5])