Скачать или смотреть Resolving NameError When Importing Variables in Python's Config Files

Learn how to correctly import variables from a config.py file into your main Python script and overcome the `NameError`.
---
This video is based on the question https://stackoverflow.com/q/74452890/ asked by the user 'user9060784' ( https://stackoverflow.com/u/9060784/ ) and on the answer https://stackoverflow.com/a/74453014/ provided by the user 'CreepyRaccoon' ( https://stackoverflow.com/u/18342123/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: Python, Import config.py

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l...
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Understanding the Import Error in Python Config Files

When working on a Python project, it’s common to separate configuration settings into a dedicated file, such as config.py. However, many beginners face a challenge when trying to use variables defined in this config file from their main script. This often leads to a frustrating NameError, which can derail your coding flow and create confusion about how to properly access your configurations.

In this guide, we'll explore how to correctly import variables from a config.py file into your main Python script and resolve common issues such as the NameError you might encounter.

The Problem: NameError When Accessing Variables

Let’s consider a simple example. You have two Python files:

config.py: This file sets up your configuration variables.

main.py: This is your primary script where you want to use those variables.

Here's what your files might look like:

config.py

[[See Video to Reveal this Text or Code Snippet]]

main.py (initial attempt)

[[See Video to Reveal this Text or Code Snippet]]

When you run main.py, you might see the following error message:

[[See Video to Reveal this Text or Code Snippet]]

The crucial part of the error message is that white is not recognized in main.py. This can be confusing as you did import config but the variable wasn’t transferred directly into the main script’s namespace.

The Solution: Correctly Importing Variables

To solve this issue, you need to specify how to access the variables from the config module. Here’s the correct way to import the variable white into your main script:

main.py (correct version)

[[See Video to Reveal this Text or Code Snippet]]

Explanation of the Fix

Using from ... import ...: The statement from config import white directly imports the variable white from the config module. This allows you to use white in main.py without prefixing it with config..

Why It Works: By using this import method, Python brings the variable white into the local scope of your main.py file, thus eliminating the NameError.

Handling Multiple Variables

If you have more than one variable in your config.py, the import statement can also be extended easily. For instance, if your config.py has several color definitions:

config.py

[[See Video to Reveal this Text or Code Snippet]]

You can import all the color variables in a single line by doing the following:

[[See Video to Reveal this Text or Code Snippet]]

Now, you have access to all three variables in your main script.

Conclusion

By understanding how Python’s import system works, you can effectively manage your configuration files and access your variables without running into common pitfalls like NameError. This simple adjustment from import config to from config import white can save you time and frustration as you build out your Python applications.

Always remember, when you want to use a variable from a different module, make sure to either import it correctly or reference it with its module prefix. Happy coding!