Python：骇客在不属于其类别的物件上呼叫方法 [英] Python: Hack to call a method on an object that isn't of its class

问题描述

假设您定义了一个类，该类具有执行一些复杂处理的方法：

Assume you define a class, which has a method which does some complicated processing:

class A(object):
    def my_method(self):
        # Some complicated processing is done here
        return self

现在您要在另一个类中的某个对象上完全使用该方法。例如，您要执行 A.my_method（7）。

And now you want to use that method on some object from another class entirely. Like, you want to do A.my_method(7).

这是您得到的： TypeError：未绑定方法my_method（）必须以实例作为第一个参数（而不是int实例）来调用。。

现在，是否有可能入侵事物，所以您可以在 7 上调用该方法？我想避免移动或重写功能。 （请注意，该方法的逻辑确实取决于 self 。）

Now, is there any possibility to hack things so you could call that method on 7? I'd want to avoid moving the function or rewriting it. (Note that the method's logic does depend on self.)

一个说明：我知道有些人会想要这样说：您做错了！您正在滥用Python！您不应该这样做！是的，我知道，这是我想做的一件可怕的事情。我在问是否有人知道该怎么做，而不是向我宣告我不应该这样做。

One note: I know that some people will want to say, "You're doing it wrong! You're abusing Python! You shouldn't do it!" So yes, I know, this is a terrible terrible thing I want to do. I'm asking if someone knows how to do it, not how to preach to me that I shouldn't do it.

推荐答案

当然，我不建议您在实际代码中执行此操作，但是可以，可以，您可以访问类的内部并将其方法用作函数：

Of course I wouldn't recommend doing this in real code, but yes, sure, you can reach inside of classes and use its methods as functions:

class A(object):
    def my_method(self):
        # Some complicated processing is done here
        return 'Hi'

print(A.__dict__['my_method'](7))
# Hi

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