python - Python 类内部的继承

Question

我需要这样的东西

class Parent(object): 
    class Base(object):
        def __init__(self, a, b):
            self.a = a
            self.b = b


    class Derived(Base):
        def __init__(self, a, b, c):
            super(Derived,self).__init__(a, b)
            self.c = c

        def doit():
            pass

parent = Parent()
derived = parent.Derived(x,y,z)
derived.doit()

当我尝试运行此程序时，出现以下错误:NameError:名称“Derived”未定义

我尝试用“Base”代替 super() 中的“Derived” - 没有帮助

Answer 1

类继承不会改变父类。在这种情况下，您的 Parent 类仅包含原始 Base 类，而不包含派生类。

你可以简单地使用猴子补丁来解决这个问题，

class Parent(object): 
    pass


class Base(object):
    def __init__(self, a, b):
        self.a = a
        self.b = b


class Derived(Base):
    def __init__(self, a, b, c):
        super(Derived,self).__init__(a, b)
        self.c = c

    def doit(self):
        pass

Parent.Derived = Derived

parent = Parent()
x, y , z = 1, 1, 1
derived = parent.Derived(x,y,z)
derived.doit()