如何在Python中将关键字参数添加到派生类的构造函数中? [英] How do I add keyword arguments to a derived class's constructor in Python?

问题描述

我想在派生类中添加关键字参数，但无法弄清楚该怎么做.尝试显而易见的

I want to add keyword arguments to a derived class, but can't figure out how to go about it. Trying the obvious

class ClassA(some.package.Class):

    def __init__(self, *args, **kwargs):
        super(ClassA, self).__init__(*args, **kwargs)

class ClassB(ClassA):

    def __init__(self, *args, a='A', b='B', c='C', **kwargs):
        super(ClassB, self).__init__(*args, **kwargs)
        self.a=a
        self.b=b
        self.c=c

失败，因为我无法列出类似ClassB的__init__的参数.还有

fails because I can't list parameters like that for ClassB's __init__. And

class ClassB(ClassA):

    def __init__(self, *args, **kwargs):
        super(ClassA, self).__init__(*args, **kwargs)
        self.a=a
        self.b=b
        self.c=c

当然不起作用，因为未指定新关键字.

of course doesn't work because the new keywords aren't specified.

如何为派生类的__init__添加关键字参数?

How do I add keyword arguments to the __init__ for a derived class?

推荐答案

尝试这样做:

class ClassA(object):
    def __init__(self, *args, **kwargs):
        pass

class ClassB(ClassA):
    def __init__(self, *args, **kwargs):            
        self.a = kwargs.pop('a', 'A')
        self.b = kwargs.pop('b', 'B')
        self.c = kwargs.pop('c', 'C')
        super(ClassB, self).__init__(*args, **kwargs)

有效地将关键字参数a，b和c添加到ClassB，同时将其他关键字参数传递给ClassA.

Effectively you add the keyword arguments a, b and c to ClassB, while passing on other keyword arguments to ClassA.

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