Handling Imports Within Imported Files: Tech Support Guide
When developing larger applications or libraries, organizing your code into modules and packages becomes essential. Properly handling imports within imported files can ensure a clean and efficient codebase. This guide will cover key concepts, best practices, and techniques for managing imports within imported files.
Import Organization in Python
In Python, there are two primary ways to import modules and functions: using the import statement or the from ... import statement. Both methods have their use cases and best practices associated with them.
Regular Import Statement
Using the regular import statement, you can import an entire module or package. For example:
import os
When using the regular import statement, accessing the functions or variables requires qualifying them with the module name, e.g., os.path.join(...).
From Import Statement
The from ... import statement allows you to import specific functions or variables directly into your namespace. For example:
from datetime import datetime, timedelta
This approach enables you to use the imported functions without qualifying them with the module name, e.g., datetime.now() becomes datetime() in your code. However, it may lead to naming conflicts if identical names exist in different modules or if multiple functions are imported from the same module.
Organizing and Importing from a Common File
It's common practice to have a common_file.py that contains functions required by the main program. common_file.py may import other files that contain the necessary parts of the codebase.
Importing in common_file.py
When importing in common_file.py, consider grouping the imports based on type (standard library, third-party packages, and local packages). This approach makes it easier to identify and manage dependencies.
## common\_file.py
import os
import sys
import numpy as np
import pandas as pd
from .only\_main\_required import func1, func2
data\_uses = {
'numpy': np,
'pandas': pd,
}
Importing Functions from common_file.py
In the main program, you can import the functions from the common_file.py using either the regular import statement or the from ... import statement.
Best Practices and Tips
-
Avoid using
from ... import *as it can lead to unwanted imports and naming conflicts. - Import only what you need to reduce the overhead of loading unnecessary functions or variables.
-
Use relative imports (
from .module import ...) for imports within the same package. -
Use absolute imports (
from package.module import ...) for imports from other packages or the standard library.
Summary
Handling imports within imported files is an essential aspect of maintaining a clean and organized codebase. By following the best practices outlined here, such as grouping imports, importing only what you need, and preferring relative imports, you will create a more manageable and efficient code structure.