__getattr__，getattribute，setattr，delattr的区别

Posted 2021-01-06

class C:
    def __getattr__(self, name):
        print(1)
        return super().__getattr__(name)

    def __getattribute__(self, name):
        print(2)
        return super().__getattribute__(name)

    def __setattr__(self, name, value):
        print(3)
        super().__setattr__(name, value)

    def __delattr__(self, name):
        print(4)
        super().__delattr__(name)

c = C()
c.x
# 显示结果为：

Traceback (most recent call last):
2
  File "E:/Python Program/test.py", line 128, in <module>
1
    c.x
  File "E:/Python Program/test.py", line 113, in __getattr__
    return super().__getattr__(name)
AttributeError: ‘super‘ object has no attribute ‘__getattr__‘

原因： 
首先c.x会先调用getattribute()魔法方法，打印2；
然后调用super().getattribute()，找不到属性名x，
因此会紧接着调用getattr()魔法方法，于是打印1，
然后调用super().getattr()。但是Python会告诉你AttrError，super对象木有getattr()!!