#描述符

class test:

    def __get__(self, instance, owner):

        print('---get方法')

    def __set__(self, instance, value):

        print('---set方法')

    def __delete__(self, instance):

        print('---delete方法')

class test2:

    name = test()#描述符代理了test2类里的name属性

t1 = test2()

#调用了被描述符代理的属性，执行__get__()方法

t1.name #---get方法

#赋值了被描述符代理的属性，执行__set__()方法

t1.name = 1 #---set方法

#赋值了被描述符代理的属性，执行__delete__()方法

del t1.name #---delete方法

#非数据描述符

class test:

    def __get__(self, instance, owner):

        print('get方法')

class test2:

    name = test()#描述符代理了test2类里的name属性

t1 = test2()

#在实例对象里中创建了name属性，并赋值chen

t1.name = 'chen'

print(t1.__dict__) #{'name': 'chen'}

#数据描述符

class Typed:

    def __init__(self,key,value_type):

        self.key = key

        self.value_type = value_type

    def __get__(self, instance, owner):

        print('get方法')

        return  instance.__dict__[self.key]

    def __set__(self, instance, value):

        print('set方法')

        if not isinstance(value,self.value_type): #判断类型

            raise TypeError('传入的类型不是',self.value_type)

        instance.__dict__[self.key] = value

    def __delete__(self, instance):

        print('delete方法')

        instance.__dict__.pop(self.key)

class People:

    name = Typed('name',str) #数据描述符代理属性

    age = Typed('age',int) #数据描述符代理属性

    def __init__(self,name,age):

        self.name = name #赋值操作，执行__set__方法

        self.age = age

#测试

p1 = People('chen',21)

print(p1.__dict__) #{'name': 'chen', 'age': 21}

p1 = People('chen','21') #报错：TypeError: ('传入的类型不是', <class 'int'>)

#数据描述符

class Typed:

    def __init__(self,key,value_type):

        self.key = key

        self.value_type = value_type

    def __get__(self, instance, owner):

        print('get方法')

        return  instance.__dict__[self.key]

    def __set__(self, instance, value):

        print('set方法')

        if not isinstance(value,self.value_type): #判断类型

            raise TypeError('传入的类型不是',self.value_type)

        instance.__dict__[self.key] = value

    def __delete__(self, instance):

        print('delete方法')

        instance.__dict__.pop(self.key)

#限制赋值类型的装饰器

def deco(**kwargs):

    def warapper(obj):

        for key,val in kwargs.items():

            setattr(obj,key,Typed(key,val)) #在装饰器中给类属性实现描述符代理

        return obj

    return warapper

@deco(name=str,age=int) #@wrapper ===>People=wrapper(People)

class People:

    #使用装饰器取代了以下两步

    # name = Typed('name',str) #数据描述符代理属性

    # age = Typed('age',int) #数据描述符代理属性

    def __init__(self,name,age):

        self.name = name #赋值操作，执行__set__方法

        self.age = age

#测试

p1 = People('chen',21)

'''

输出:

set方法

set方法

'''

print(p1.__dict__) #{'name': 'chen', 'age': 21}

class Demoproperty:

    def __init__(self,func):

        print('----+')

        self.func = func

class People:

    def __init__(self,name,age):

        self.name = name #赋值操作，执行__set__方法

        self.age = age

    @Demoproperty #eat=Demoproperty(eat)

    def eat(self):

        print("%s在吃饭"%self.name)

p1 =People('chen',21)

p1.eat.func(p1) #chen在吃饭

瞎搞

#非数据描述符

class Demoproperty:

    def __init__(self,func):

        self.func = func

    def __get__(self, instance, owner):

        print('get')

        res = self.func(instance)

        return res

class People:

    def __init__(self,name,age):

        self.name = name #赋值操作，执行__set__方法

        self.age = age

    #实现了添加描述符的操作

    @Demoproperty #eat=Demoproperty(eat)

    def eat(self):

        print("%s在吃饭"%self.name)

p1 =People('chen',21)

p1.eat #chen在吃饭

class ClassMethod:

    def __init__(self,func):

        self.func=func

    def __get__(self, instance, owner): #owner是类

        def feedback(*args,**kwargs):

            return self.func(owner,*args,**kwargs)

        return feedback #返回一个可以传参的方法

class People:

    @ClassMethod # say_hi=ClassMethod(say_hi)

    def say_hi(cls,name,age):

        print('我是%s，年龄%s' %(name,age))

People.say_hi('chen',21) #我是chen，年龄21

class StaticMethod:

    def __init__(self,func):

        self.func=func

    def __get__(self, instance, owner): #owner是类

        def feedback(*args,**kwargs):

            return self.func(*args,**kwargs)

        return feedback #返回一个可以传参的方法

class People:

    @StaticMethod # say_hi=ClassMethod(say_hi)

    def say_hi(name,age):

        print('我是%s，年龄%s' %(name,age))

People.say_hi('chen',21) #我是chen，年龄21