Python相互依赖的类（循环依赖） [英] Python mutually dependent classes (circular dependencies)

问题描述

我搜索了很多，但我发现主要是在Python中递归编程的例子。所以这里有个问题：

I've searched a lot, but what I find is mainly examples of recursive programming in python. So here goes the question:

如何实现这个？

class A:
    b = B()

class B:
    a = A()

推荐答案

在Python中，一切都是动态的 - 甚至是类声明。在初始声明之后，没有什么可以阻止您修改类的内容：

Everything is dynamic in Python - even the class declarations. There's nothing to stop you modifying the contents of a class after the initial declaration:

class A:
    pass

class B:
    a = A()

A.b = B()

注意：如果你不熟悉Python， pass 关键字只是允许你说'什么都不在这里' - 它不重要除非A类与此示例中一样为空！

NB: If you're not that familiar with Python, the pass keyword simply allows you to say 'nothing here' - it's not important unless class A is as empty as it is in this example!

这篇关于Python相互依赖的类（循环依赖）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！