Python：访问“模块范围” vars [英] Python: accessing "module scope" vars

问题描述

我目前正在学习Python，我必须处理Python 2.7项目。

I'm currently learning Python, and I have to work on a Python 2.7 project.

在模块本身的函数中访问模块范围

Accessing "module scope" variables in functions of the module itself is a bit confusing for me, and I didn't succeed in finding a satisfying way.

我的尝试到目前为止：

方式1：

my_module.py

my_module.py

my_global_var = None

def my_func():
    global my_global_var
    my_global_var = 'something_else'

这里我认为混淆本地和模块范围的变量可能很容易。

Here I think that confusing local and "module scope" vars may be quite easy.

2：

my_module.py

my_module.py

import my_module

my_global_var = None

def my_func():
    my_module.my_global_var = 'something_else'

这里，my_module的名称在必要时不能像way 1那样容易改变。另外，将一个模块导入自己听起来很奇怪。

Here, the name of "my_module" could not be as easily changed as "way 1" when necessary. Plus, importing a module into itself sounds quite weird.

你会推荐什么？或者你会建议一些别的？感谢。

What would you recommend? Or would you suggest something else? Thanks.

推荐答案

您可能想阅读 Python的命名空间。方法1是正确的，但一般不必要，从不使用2.一个更简单的方法是只使用dict（或类或其他对象）：

You probably want to read up on Python's namespaces. Way 1 is correct but generally unnecessary, never use 2. An easier approach is to just use a dict (or class or some other object):

my_globals = {'var': None}

def my_func():
    my_globals['var'] = 'something else'

分配始终位于最内层范围，最内层范围始终首先搜索，因此需要全局关键字。在这种情况下，您没有分配到名称，因此没有必要。

Assignments always go into the innermost scope and the innermost scope is always searched first, thus the need for the global keyword. In this case you aren't assigning to a name, so it's unnecessary.

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