Скачать или смотреть Understanding Python NameError: A Guide to Correct Function Usage

This guide explains Python's `NameError` and offers a solution for correctly defining and calling functions to avoid errors.
---
This video is based on the question https://stackoverflow.com/q/63719981/ asked by the user 'Alternate275' ( https://stackoverflow.com/u/14161363/ ) and on the answer https://stackoverflow.com/a/63720068/ provided by the user 'EEEEH' ( https://stackoverflow.com/u/11258645/ ) 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 NameError and I can not understand

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 Python NameError: A Guide to Correct Function Usage

When diving into the world of Python programming, you’re likely to encounter situations where errors crop up, causing your code to fail. One common issue many novices face is the dreaded NameError. In this guide, we will explore the reason behind this error, using a specific example related to function definitions in Python, and we'll provide a clear, step-by-step solution.

What is NameError?

A NameError in Python occurs when the code references a variable or a function name that hasn’t been defined yet. This can be frustrating, especially for beginners who are trying to run their first functions.

Example Scenario

Let’s look at an example where this error made an appearance. The following function is defined:

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

Here, the function get_seconds takes three arguments (hours, minutes, and seconds) and returns the total number of seconds. However, when someone attempted to execute this function with the following code:

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

They encountered the error:

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

Understanding the Issue

The error is caused by the fact that minutes and seconds are not defined variables in the code block where they are used. Here’s a breakdown of the problems:

The variables minutes and seconds haven’t been initialized or assigned any values before they are utilized in the function call.

When Python encounters a name that it doesn’t recognize within the program’s scope, it raises a NameError.

How to Fix the NameError

Getting rid of the NameError is straightforward: Make sure to provide actual values for the function parameters when calling it. Here’s how you can re-write the function calls to work correctly:

Solution Steps:

Define the Time Variables Clearly: Instead of using undefined variables, provide explicit numerical values for hours, minutes, and seconds.

Adjust the Function Call:
You can call the function like this:

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

In this corrected version:

amount_a is calculated using 2 hours, 30 minutes, and 0 seconds, which equals a total of 9000 seconds.

amount_b uses 0 hours, 45 minutes, and 15 seconds, calculating to a total of 2715 seconds.

Combine the Results:
Finally, you can calculate the total:

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

Complete Example Code

Here’s the full code snippet, corrected and ready to run:

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

Conclusion

The NameError can be a stumbling block for new Python programmers, but understanding its causes and how to solve it is crucial. Always remember to define your variables before using them, and ensure you pass valid arguments when calling functions. With practice, these concepts will become second nature.

Happy coding! If you have further questions or issues with Python, feel free to ask in the comments below!