处理 Python 模块中的循环依赖? [英] Handle circular dependencies in Python modules?

问题描述

这又是一个案例，我在圈子里跑来跑去，我要发疯了.

我希望 Python 首先分析所有文件，以便它从一开始就知道所有标识符(我认为就像 Java 一样).

我有一个main.py"和一个gui.py".每个文件都包含一个类，它使用另一个文件中的类.当我尝试运行main.py"时，解释器导入gui"，然后在gui.py"中导入main"，然后处理整个主模块并说:Tee-hee，没有类使用 gui.py 中的给定名称."

如何在 Python 中轻松处理循环依赖?

解决方案

我想我会将其扩展为答案而不是评论.

值得注意的是循环导入通常是糟糕设计的标志:与其要求语言适合您的设计，为什么不改变该设计?

在python中有解决这个问题的方法::>

• 不错的选择:重构您的代码，不要使用循环导入.
• 糟糕的选择:将您的 import 语句之一移动到不同的范围.

但是不，您不能预解析文件.这不是 Python 的工作方式，如果您研究一下 Python 的工作方式，原因就很明显了.

this is a case again where I'm running around in circles and I'm about to go wild.

I wish Python would analyze all files at first, so that it would know all identifiers from the beginning (I think like Java does).

I have a "main.py" and a "gui.py". Every file contains a class, that makes use of the class in the other file. When I try to run "main.py", the interpreter imports "gui", then in "gui.py" it imports "main", then it processes the whole main module and says: "Tee-hee, there is no class with the given name in gui.py."

How can I handle circular dependencies in Python with minimum fuss?

解决方案

I thought I'd expand this into an answer instead of a comment.

It's worth noting that circular imports are generally a sign of bad design: instead of demanding the language suit your design, why not change that design?

There are ways around this problem in python:

• The good option: Refactor your code not to use circular imports.
• The bad option: Move one of your import statements to a different scope.

But no, you can't pre-parse files. That's not the way Python works, and if you look into how Python works, it's pretty obvious why.

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