How to Dynamically Include and Call Functions from Multiple Python Modules efficiently

Discover how to dynamically load Python modules and conditionally call their functions using `glob` and `os` libraries in this detailed guide.
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Introduction

Are you working on a Python project where you need to dynamically load multiple Python files from a directory? Would you like to conditionally call functions if they exist within those modules? If your answer is yes, then you’re in the right place!

In this guide, we’ll guide you through the process of loading Python modules from a folder and checking whether they contain specific functions. Let’s dive in!

The Problem

While building a Python application, you may find yourself needing to manage code spread across multiple files. Sometimes these files may contain functions that you need to access based on certain conditions. A common scenario might be where:

You have an unknown number of Python files in a directory.

Each file may or may not contain a specific function you want to call (for example, sayBye).

Here’s what needs to be accomplished:

List an inventory of .py files within a specified folder (for example, "modules").

Import these files into a manageable data structure.

Conditionally call specific functions only if they exist.

Setting Up Your Project

Installation

To run the example provided in this guide, ensure you have:

Operating System: Microsoft Windows 11

Python Version: 3.10.4 or higher

Folder Structure

Your project should follow this folder structure for the example to function properly:

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Example Files

This file will be responsible for loading and using our modules.

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Sample Modules

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Expected Output

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Solving the Problem

Step 1: Iterating Over Modules

After successfully importing the modules, you want to check if the sayBye function is defined in each one. However, you encountered an issue where the function checks were failing.

The original code looped through the keys of the modules dictionary, which contained the filenames. Instead, you need to iterate through the dictionary’s values to access the actual module objects:

Change this line:

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To:

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Step 2: Importing Modules by Name

Another problem you faced was related to how the modules were being imported. They were essentially all imported under the same name, which led to confusion.

To address this, use the base name of the file when importing:

Modify this section:

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To:

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Final Code

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Conclusion

By following the steps detailed in this guide, you can dynamically include Python modules and safely call their functions. Remember to always validate the functions before attempting to invoke them. Happy coding!