TL;DR Relative imports in Python packages enhance portability and maintainability by allowing modules to be imported regardless of the package’s location, especially when your library is under a src folder.

Table of Contents

• The Importance of Relative Imports in Python Packages
• Table of Contents
• Understanding Python Imports
  • Absolute Imports
  • Relative Imports
• Why Use Relative Imports in Packages
  • Portability
  • Maintainability
  • Avoiding Namespace Collisions
• Examples of Relative Imports
  • Single Dot Syntax
  • Multiple Dots Syntax
• Best Practices
• Conclusion

The Importance of Relative Imports in Python Packages

When developing Python packages, organizing your code efficiently and ensuring maintainability are crucial. One aspect that often gets overlooked is the method of importing modules within your package. This blog post will delve into why using relative imports is considered a best practice when creating Python packages.

Table of Contents

Understanding Python Imports

Before diving into relative imports, it’s essential to understand how Python handles imports in general.

Absolute Imports

Absolute imports involve specifying the complete path to the module or object you want to import, starting from the project’s root folder.

 project_root/package/module.py

from package.subpackage import my_module

Relative Imports

Relative imports, on the other hand, use a dot (.) notation to specify the current and parent packages involved.

 project_root/package/module.py

from .subpackage import my_module

• A single dot (.) refers to the current package level.
• Two dots (..) refer to the parent package level.

Why Use Relative Imports in Packages

When creating a package, especially one that might be distributed or used in different environments, relative imports offer several advantages.

Portability

Relative imports make your package more portable. If your library is under a src folder or if the package’s location within a project changes, relative imports will continue to work since they don’t rely on the absolute path.

Example:

Suppose you have a package structure:

project_root/
├── src/
│   └── my_package/
│       ├── __init__.py
│       ├── module_a.py
│       └── module_b.py
└── main_app/
    └── ...

If you move my_package into main_app, absolute imports inside my_package would break, whereas relative imports would still function correctly.

Maintainability

Using relative imports reduces the need to refactor import statements when the package hierarchy changes. This makes your codebase easier to maintain over time.

Avoiding Namespace Collisions

Relative imports help prevent conflicts with modules of the same name in the global namespace or other installed packages.

Examples of Relative Imports

Single Dot Syntax

Importing a module from the same package:

 my_package/module_a.py

from . import module_b

Multiple Dots Syntax

Importing from the parent package:

 my_package/subpackage/module_c.py

from .. import module_a

Importing from a sibling package:

 my_package/subpackage/module_c.py

from ..subpackage2 import module_d

Best Practices

• Use Relative Imports for Intra-Package Imports: This ensures that your package’s internal modules can be imported regardless of where the package is installed.
• Avoid Using Relative Imports in Scripts: Relative imports are meant for packages, not standalone scripts. If you’re writing a script that will be executed directly, use absolute imports.
• Be Consistent: Stick to one style of imports within your package to maintain readability and reduce confusion.

Conclusion

Relative imports are a powerful tool for maintaining clean, portable, and maintainable code within Python packages. By relying on the package’s internal structure rather than its position in the project’s hierarchy, you make your code more resilient to changes and easier to manage.

Remember: When developing Python packages, favor relative imports for internal modules to adhere to best practices and enhance your package’s robustness.