Python __getattribute__ 和 __setattr__

Question

我有以下代码:

#-*-coding:utf-8-*-
class A(object):
    def __init__(self, x):
        self.x = x

    def __getattr__(self, name):      # `__getattr__` will be called undefined attribute
        print "get: ", name
        return self.__dict__.get(name)

    def __setattr__(self, name, value):
        print "set:", name, value
        self.__dict__[name] = value

    def __getattribute__(self, name): # `__getattribute__` will be called all attributes
        print "attribute:", name
        return object.__getattribute__(self, name)

if __name__ == "__main__":
    a = A(10)
    print '---------------'
    a.x
    print '---------------'
    a.y = 20
    print '---------------'
    a.z

结果是:

set: x 10
attribute: __dict__
---------------
attribute: x
---------------
set: y 20
attribute: __dict__
---------------
attribute: z
get:  z
attribute: __dict__    

当我调用a=A(10)时，为什么调用__getattribute__？这是我的想法: __init__ 中有 self.x = x ，并且 __setattr__ catch __init__, self.__dict__[name] = value catch __getattrbute__。因此，调用了 __getattribute__ 。我的想法对吗？怎么了？

Answer 1

箭头指向 __setattr__ 调用 __getattribute__ 的位置:

def __setattr__(self, name, value):
    print "set:", name, value
    self.__dict__[name] = value
#       ^ attribute access!

__getattribute__ 处理所有显式属性查找，包括 __dict__。我相信这是你已经得出的结论；我不太明白你想说什么。