Скачать или смотреть How to Pass Command Line Arguments to a Python Function in a Script

Learn how to pass command line arguments to a Python function in scripts effectively, avoiding the use of os.system.
---
This video is based on the question https://stackoverflow.com/q/63243241/ asked by the user 'SteRinaldi' ( https://stackoverflow.com/u/14046726/ ) and on the answer https://stackoverflow.com/a/63243459/ provided by the user 'scott' ( https://stackoverflow.com/u/10653615/ ) 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: Passing command line arguments to Python function in script

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.
---
How to Pass Command Line Arguments to a Python Function in a Script

When working with Python scripts, you often need to pass information to your functions. A common way to do this is through command line arguments. If you're utilizing a function that accepts command line arguments with the optparse module, you may wonder about the best way to invoke this function from another script without resorting to os.system. In this guide, we’ll explore effective methods to accomplish this task.

Understanding the Problem

You might have a function defined like this:

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

This function utilizes optparse to gather command line arguments (-i for input and -o for output). When trying to call this function from another Python script, the challenge arises—how do you provide these arguments correctly without executing a shell command like os.system('foo -i input_path -o output_path')?

Solutions to the Problem

1. Refactor the Function to Accept Parameters

The best and cleanest approach is to modify the function foo so that it accepts parameters directly. This allows you to call the function more flexibly from another script. Here's how you can refactor it:

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

In this refactored version:

Input and Output Parameters: The function now accepts input and output as parameters, allowing you to pass the values directly when calling foo from another script.

Keeping Command Line Functionality: The command line argument processing remains intact. If the arguments are supplied through the command line, they’ll still override any values passed directly.

2. Use the Subprocess Module

If you prefer to keep the original function as is and want to call it from another script, you can consider using the subprocess module. This module allows for more control over how you handle command line arguments without umbrella commands like os.system:

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

In this example:

Subprocess Call: The subprocess.run method is used here to run a separate Python script (your_script.py in this case) with the necessary command line arguments passed as a list.

Flexibility: This method allows you to maintain the logic for command line argument handling in your original function while effectively calling it from another script.

Conclusion

Passing command line arguments to a function in Python scripts can be achieved in a couple of ways. By refactoring the function to accept parameters, you make it much easier to call from other scripts, enhancing code reusability. Alternatively, using the subprocess module allows you to invoke other scripts with command line arguments without using os.system. Choose the method that best fits your needs, and enhance your Python scripting capabilities today!