Python有什么东西像匿名内部类的Java？ [英] Does Python have something like anonymous inner classes of Java?

问题描述

在Java中，您可以使用匿名内部类来内联定义一个新类。这在需要重写类的单个方法时非常有用。

In Java you can define a new class inline using anonymous inner classes. This is useful when you need to rewrite only a single method of the class.

假设您想要创建 OptionParser 只覆盖一个方法（例如 exit（））。在Java中你可以这样写：

Suppose that you want create a subclass of OptionParser that overrides only a single method (for example exit()). In Java you can write something like this:

new OptionParser () {

    public void exit() {
        // body of the method
    }
};

这段代码创建一个匿名类，扩展 OptionParser 并覆盖 exit（）方法。

This piece of code creates a anonymous class that extends OptionParser and override only the exit() method.

Python中有类似的用法吗？

There is a similar idiom in Python? Which idiom is used in these circumstances?

推荐答案

您可以使用 type（name，bases，dict） 内建功能即时创建类。例如：

You can use the type(name, bases, dict) builtin function to create classes on the fly. For example:

op = type("MyOptionParser", (OptionParser,object), {"foo": lambda self: "foo" })
op().foo()

由于OptionParser不是new-style类，你必须在基类列表中显式包含 object 。

Since OptionParser isn't a new-style class, you have to explicitly include object in the list of base classes.

这篇关于Python有什么东西像匿名内部类的Java？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！