getattribute getattr

最新推荐文章于 2022-05-12 16:23:50 发布

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本文介绍了一个使用Python实现的类D，该类通过重写__getattribute__和__getattr__方法来自定义对象属性的访问方式。当尝试访问'test'属性时会触发特定的行为，并在未找到属性时返回默认值。

class D(object):

    def __init__(self):
        self.default = 0.0
        self.test = 20
        self.test2 = 21

    def __getattribute__(self, name):
        try:
            if name == "test":
                print ("__getattribute__ name = %s" % name)
                return self.test        #This will default call same function "__getattribute__", can fix by object
            else:
                print ("__getattribute__ name = %s" % name)
                return object.__getattribute__(self, name)
        except AttributeError:
            print "getattribute error"
            raise

    def __getattr__(self, name):
        print ("__getattr__ name = %s" % name)
        print ("self.default=%s" % self.default)
        return self.default

if __name__ == "__main__":

    d = D()
    #print d.test       #This will caused recurison error because it call the same function, your getattribute
    print d.test2
    print d.ts           #When "__getattribute__" raise error, it will call in "__getattr__".