AttributeError：'property'对象没有属性 [英] AttributeError: 'property' object has no attribute

问题描述

Python（2.6）看起来没有理由，任何人都可以看到这个代码的问题？

Python (2.6) seems to be derping for no reason, can anyone see a problem with this code?

class DB ():
    def doSomething (self, str):
        print str

class A ():
    __db = DB()

    @staticmethod
    def getDB ():
        return A.__db

    db = property(getDB)


A.db.doSomething("blah")

无效例外：

AttributeError：'property'object没有属性'doSomething'

AttributeError: 'property' object has no attribute 'doSomething'

理解一个属性在访问时会自动运行它的getter，所以为什么会抱怨一个属性对象，为什么不能找到我清楚可用的方法？

It was my understanding that a property would automatically run its getter when accessed, so why is it complaining about a property object, and why isn't it finding my clearly available method?

推荐答案

除了需要继承 object ，属性只能在实例上使用。

In addition to needing to inherit from object, properties only work on instances.

a = A()
a.db.doSomething("blah")

要使一个属性在类上工作，你可以定义一个元类。 （类是元类的实例，因此定义在元类上的属性在类上工作，就像在该类的实例上的类上定义的属性一样。）

To make a property work on the class, you can define a metaclass. (A class is an instance of a metaclass, so properties defined on the metaclass work on the class, just as properties defined on a class work on an instance of that class.)

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