带有子模块和函数的 Python 模块 [英] Python modules with submodules and functions

问题描述

我有一个关于像 numpy 这样的库如何工作的问题.当我导入 numpy 时，我可以访问大量内置类、函数和常量，例如 numpy.array、numpy.sqrt等

I had a question on how libraries like numpy work. When I import numpy, I'm given access to a host of built in classes, functions, and constants such as numpy.array, numpy.sqrt etc.

但是在 numpy 中还有其他子模块，例如 numpy.testing.

But within numpy there are additional submodules such as numpy.testing.

这是怎么做到的?以我有限的经验，带有子模块的模块只是带有 __init__.py 文件的文件夹，而带有函数/类的模块是实际的 python 文件.如何创建模块文件夹"?也有函数/类?

How is this done? In my limited experience, modules with submodules are simply folders with a __init__.py file, while modules with functions/classes are actual python files. How does one create a module "folder" that also has functions/classes?

推荐答案

包含 .py 文件和 __init__.py 的文件夹称为 package.包含类和函数的文件之一是 module.文件夹嵌套可以给你子包.

A folder with .py files and a __init__.py is called a package. One of those files containing classes and functions is a module. Folder nesting can give you subpackages.

例如，如果我有以下结构:

So for example if I had the following structure:

  mypackage
     __init__.py
     module_a.py
     module_b.py
        mysubpackage
             __init__.py
             module_c.py
             module_d.py

我可以导入 mypackage.module_a 或 mypackage.mysubpacakge.module_c 等等.

I could import mypackage.module_a or mypackage.mysubpacakge.module_c and so on.

您还可以通过将该代码放置在 __init__.py 中来将函数添加到 mypackage(如您提到的 numpy 函数).虽然这通常被认为是丑陋的.

You could also add functions to mypackage (like the numpy functions you mentioned) by placing that code in the __init__.py. Though this is usually considered to be ugly.

如果你看看 numpy 的 __init__.py 你会在那里看到很多代码——其中很多是定义这些顶级类和函数.__init__.py 代码是加载包时执行的第一件事.

If you look at numpy's __init__.py you will see a lot of code in there - a lot of this is defining these top-level classes and functions. The __init__.py code is the first thing executed when the package is loaded.

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