访问“模块范围"；瓦斯 [英] accessing "module scope" vars

问题描述

我目前正在学习Python，我必须从事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作用域"变量对我来说有点令人困惑，并且我没有成功找到令人满意的方法.

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.

到目前为止，我的尝试:

My attempts so far:

方法1:

my_module.py

my_module.py

my_global_var = None

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

在这里，我认为混淆本地变量和模块范围"变量可能很容易.

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

方式2:

my_module.py

my_module.py

import my_module

my_global_var = None

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

在这里，"my_module"的名称在必要时不能像"way 1"那样容易地更改.另外，将模块导入自身听起来很奇怪.

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.

您会推荐什么?还是您会提出其他建议?谢谢.

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

推荐答案

您可能想阅读

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'

赋值总是进入最内部的范围，并且总是首先搜索最内部的范围，因此需要global关键字.在这种情况下，您无需分配名称，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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