getattr的最大递归深度错误

yas*_*sar 1 python recursion exception-handling descriptor

我有这个代码;

class NumberDescriptor(object):
    def __get__(self, instance, owner):
        name = (hasattr(self, "name") and self.name)
        if not name:
            name = [attr for attr in dir(owner) if getattr(owner,attr) is self][0]
            self.name = name
        return getattr(instance, '_' + name)
    def __set__(self,instance, value):
        name = (hasattr(self, "name") and self.name)
        if not name:
            owner = type(instance)
            name = [attr for attr in dir(owner) if getattr(owner,attr) is self][0]
            self.name = name
        setattr(instance, '_' + name, int(value))

class Insan(object):
    yas = NumberDescriptor()

a = Insan()
print a.yas
a.yas = "osman"
print a.yas
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我在行中获得最大递归深度错误name = [attr for attr in dir(owner) if getattr(owner,attr) is self][0].我希望该行获取用于当前描述符实例的变量的名称.谁能看到我在这里做错了什么?

Cha*_*ffy 9

getattr()呼叫在呼唤你__get__.

解决此问题的一种方法是显式调用超类,object:

object.__getattribute__(instance, name)
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或者,更清楚:

instance.__dict__[name]
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  • 在一般情况下,`instance .__ dict __ [name]`对于非数据描述符可能会失败.`NumberDescriptor`是一个数据描述符,所以在这种情况下它应该工作. (3认同)