Python在父类中使用派生类的方法？ [英] Python using derived class's method in parent class?

问题描述

我可以强制父类调用派生类的函数版本吗？

Can I force a parent class to call a derived class's version of a function?

class Base(object):
    attr1 = ''
    attr2 = ''

    def virtual(self):
        pass               # doesn't do anything in the parent class

    def func(self):
        print "%s, %s" % (self.attr1, self.attr2)
        self.virtual()

以及从中派生的类

class Derived(Base):
    attr1 = 'I am in class Derived'
    attr2 = 'blah blah'

    def virtual(self):
        # do stuff...
        # do stuff...

清除模糊性：

d = Derived()
d.func()         # calls self.virtual() which is Base::virtual(), 
                 #  and I need it to be Derived::virtual()

推荐答案

如果你实例化ea 派生（比如 d = Derived（））， .virtual 由 d.func（） 调用 Derived.virtual 。如果没有涉及 Derived 的实例，则 Derived.virtual没有合适的 self 所以当然不可能打电话给它。

If you instantiate a Derived (say d = Derived()), the .virtual that's called by d.func() is Derived.virtual. If there is no instance of Derived involved, then there's no suitable self for Derived.virtual and so of course it's impossible to call it.

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