为什么以及如何使用 Python 的 super(type1, type2)? [英] why and how to use Python's super(type1, type2)?

问题描述

super 有 2 个参数，

super has 2 args,

super(type, obj_of_type-or-subclass_of_type)

我了解如何以及为什么使用 super 并且第二个参数是 obj_of_type.但我不明白第二个参数是子类的问题.

I understand how and why to use super with the 2nd arg being obj_of_type. But I don't understand the matter for the 2nd arg being subclass.

谁能说明原因和方法?

推荐答案

如果你想调用一个实例方法，你可以传递一个对象.如果要调用类方法，则传递一个类.

You pass an object if you want to invoke an instance method. You pass a class if you want to invoke a class method.

将super() 用于类方法的经典示例是使用工厂方法，您希望在其中调用所有超类工厂方法.

The classic example for using super() for class methods is with factory methods, where you want all the superclass factory methods to be called.

class Base(object):
    @classmethod
    def make(cls, *args, **kwargs):
        print("Base.make(%s, %s) start" % (args, kwargs))
        print("Base.make end")

class Foo(Base):
    @classmethod
    def make(cls, *args, **kwargs):
        print("Foo.make(%s, %s) start" % (args, kwargs))
        super(Foo, cls).make(*args, **kwargs)
        print("Foo.make end")

class Bar(Base):
    @classmethod
    def make(cls, *args, **kwargs):
        print("Bar.make(%s, %s) start" % (args, kwargs))
        super(Bar, cls).make(*args, **kwargs)
        print("Bar.make end")

class FooBar(Foo,Bar):
    @classmethod
    def make(cls, *args, **kwargs):
        print("FooBar.make(%s, %s) start" % (args, kwargs))
        super(FooBar, cls).make(*args, **kwargs)
        print("FooBar.make end")

fb = FooBar.make(1, 2, c=3)

"在 Python 中调用超类的类方法" 有一个现实世界的例子.

"Invoking a superclass's class methods in Python" has a real-world example.

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