python中__setattr__的属性设置

# attr.pyclass AcessControl:

    def __init__(self):

        self.hobby = "basketball"               # 会调用下面的__setattr__方法

    def __setattr__(self, key, value):

        # self.name = "xxxx"                    # 不能在__setattr__上使用self.attr,会导致递归应用循环

        print("access control set attr ...")                if key == 'age':

            self.__dict__[key] = value + 10     # 通过内建字典来保存属性数据

        else:

            self.__dict__[key] = value            def __delattr__(self, item):

        print("del item[%s]" % item)            def __getattr__(self, item):

        print("get item[%s]" % item)    def test_access_control():

    ac = AcessControl()

    ac.age = 10         # 调用__setattr__

    print(ac.age)       # 直接输入值，没有调用__getattr__

    print(ac.hobby)     # 当属性有值时，也就是非None是不会调用__getattr__方法的，如果没有值，即None就会调用__getattr__方法

    del ac.age          # 调用__delattr__

    print(ac.name)      # 调用__getattr__,调用未定义的属性时候就会回调这个函数并且返回Noneif __name__ == '__main__':    test_access_control()>>> python attr.py      # 2.x & 3.x