# 要管理鸡鸭鹅,如何能够最方便的管理,就是我说同一句话,他们都能理解
# 他们拥有相同的方法
class JI:def bark(self):print('咯咯咯')def spawn(self):print('下鸡蛋')
​
class Duck:def bark(self):print('嘎嘎嘎')def spawn(self):print('下鸭蛋')
​
class Er:def bark(self):print('鹅鹅鹅')def spawn(self):print('下鹅蛋')j = JI()
y = Duck()
e = Er()
​
def mange(obj):obj.spawn()
​
mange(j)  # 下鸡蛋
mange(y)  # 下鸭蛋
mange(e)  # 下鹅蛋

# isinstance
def add_num(a,b):if isinstance(a,int) and isinstance(b,int):return a+breturn None
​
print(add_num('100',10))  # None


​
# issubclass
class Animal:def eat(self):print('动物得吃东西...')
​
class Pig(Animal):def eat(self):print('猪要吃猪食...')class Tree:def light(self):print('植物要光合作用')
​
pig = Pig()
t = Tree()def mange(obj):if issubclass(type(obj),Animal):obj.eat()else:print('不是动物!')mange(pig)  # 猪要吃猪食
mange(t)  # 不是动物!

# 类中的魔法函数
class Person(object):def __init__(self,name,age):self.name = nameself.age = agedef __str__(self):return '这是一个person对象 name:%s age:%s' %(self.name,self.age)p = Person('jack',18)
print(p)

import time
​
class Person(object):def __init__(self,name,age):self.name = nameself.age = agedef __del__(self):print('del run')p =Person('jack',18)
​
del p
​
time.slepp(5)
print('over')
​
# del run 过5秒后 over

class A:def __call__(self,*args,**kwargs):print('call run')a = A()
a(1,a=100)  # {1:100}

# slots未使用时
import sys
​
class Person:def __init__(self,name):self.name = namep = Person('jack')
print(sys.getsizeof(p))  # 56  字节数
​
# 开始使用slots
class Person:__slots__ = ['name']def __init__(self,name):self.name = namep = Person('jack')
print(sys.getsizeof(p))  # 48  字节数
p.age = 20  # 这时候打印,会直接报错,因为这个类的对象无法再添加新的属性
print(p.__dict__)  # 直接报错 'Person' object 没有'__dict__'

# 属性的get set del
class A:def __getattr__(self, item):print('__getattr__')def __setattr__(self,key,value):super().__setattr__(key,value)print('__setattr__')def __delattr__(self, item):print('__delattr__')a =A()
a.name = 'jack'
print(a.name)  # 'jack'

​
# 重点关注setattr与delattr
class A:def __getattr__(self, item):print('__getattr__')def __setattr__(self,key,value):print('__setattr__')self.__dict__[key] = valuedef __delattr__(self, item):print('__delattr__')self.__dict__.pop(item)a =A()
a.name = 'jack'
print(a.name)  # '__setattr__' 'jack'
​
del a.name
print(a.name)  # None

​
# __getattr__与__getattribute__同时出现时,会先调用__getattribute__方法
class A:def __getattr__(self, item):print('__getattr__')def __getattribute__(self, item):print('__getattribute__')　　　　 return super().__getattribute__(item)

# getitem,  setitem, delitem
# 第一种情况
class A:def __getitem__(self, item):print('__getitem__')def __setitem__(self,key,value):print('__setitem__')self.__dict__[key] = valuedef __delitem__(self, item):print('__delitem__')a = A()
a.['name'] = 'jack'  # '__setitem__'
print(a.name)  # 报错
​
# 第二种情况
class A:def __getitem__(self, item):print('__getitem__')retuan self.__dict__[item]def __setitem__(self,key,value):print('__setitem__')self.__dict__[key] = valuedef __delitem__(self, item):del self.__dict__[key]print('__delitem__')
​
a = A()
a.['name'] = 'jack'
print(a.['name'])  # '__setitem__'
del a['name']
print(a.['name'])

class MyDict(dict):def __getattr__(self, key):return  self.get(key)def __setattr__(self,key,value):self[key] = valuedef __delattr__(self, item):def self[item]
​
a = MyDict()
a['name'] = 'jack'
print(a.['name'])  # 'jack'
​
a.['age'] = 20
print(a.['age'])  # 'jack' 20

# 对象比较大小,__gt__为大于greater than,等于Be equal to,小于less than
# 下面的代码中,other指的是另一个参与比较的对象,大于和小于只要实现一个即可,符号如果不同,解释器会自动交换两个对象的位置
# 大于和小于的情况
class Student:def __init__(self,name,height,age):self.name = nameself.height = heightself.age = agedef __gt__(self, other):print('__gt__')return self.height > other.heightstu1 = Student('jack',180,28)
stu2 = Student('rose',145,27)
​
print(stu1 > stu2)  # True
print(stu1 < stu2)  # False
​
​
# 等于的情况
class Student:def __init__(self,name,height,age):self.name = nameself.height = heightself.age = agedef __eq__(self,other):print('__eq__')return self.name == other.namestu1 = Student('jack',180,28)
stu2 = Student('rose',145,27)
​
print(stu1 == stu2)  # False

class MyIter:# num传入,是用来指定迭代次数def __init__(self,num):self.num = numself.c = 0def __iter__(self):return selfdef __next__(self):self.c += 1if self.c <= self.mnum:return 'hahaha'else:raise StopIterationfor i in MyIter(10):print(i)  # 返回10个'hahaha'

# 实现一个自定义的range
class MyRange:def __init__(self,start,end,step):self.start = startself.end = endself.step = stepdef __iter__(self):return selfdef __next__(self):a = self.startself.start += self.stepif a < self.end:return aelse:raise StopIterationfor i in MyRange(1,10,2):print(i)  # 1 3 5 7 9

with open('XXXX')as f:pass

# 第一种情况
class MyOpen:def __enter__(self):print('enter...')def __exit__(self,exc_type,exc_val,exc_tb):print('exit...')print(exc_type,exc_val,exc_tb)with MyOpen() as m:pass
# enter...  exit... None None None


​
​
# 第二种情况
class MyOpen:def __enter__(self):print('enter...')def __exit__(self,exc_type,exc_val,exc_tb):print('exit...')print(exc_type,exc_val,exc_tb)with MyOpen() as m:print('start')  # 'start' 'exit''123' + 1  # 报错print('over')  # 'enter' 'over'



​
# 第三种情况
class MyOpen:def __init__(self,path):self.path = pathdef __enter__(self):self.file = open(self.path) print('enter...')return selfdef __exit__(self,exc_type,exc_val,exc_tb):print('exit...')print(exc_type,exc_val,exc_tb)self.file.close()return True  # 这里表示异常是否被处理,True为已处理,False为未处理
        with MyOpen('a.txt')as m:print(m.file.read())# 如果仍然报错,返回错误信息与Process finished with exit code 1,则异常未被处理# 如果未报错,返回Process finished with exit code 0,则异常已被处理