Overview

Introduction

In Python, when building a framework or code generation tool, you might need to programmatically build a string representing the name of a module you want to import. How would you import a module if you have it's name as a string? Here's how to do it with importlib! Note that this feature was introduced in Python 3.1 but there is a 2.7 version of importlib though less featured.

Learn more about how Python searches for imports, how the `PYTHONPATH` environment variable is used, and how to use `sys.path` in my Python import, sys.path, and PYTHONPATH Tutorial.

Learn more about Python virtual environments which allow you to create isolated Python environments with different import paths with my Python Virtual Environments Tutorial.

Use importlib to programmatically import modules

The importlib provides a simple import_module function that accepts a string name with dot separators. It works just like a normal import except it uses a string to store the name. On import, the file is executed and the module object is returned. If you only need the code run on import it is not necessary to store the returned module.

import importlib

# Contrived example of generating a module named as a string
full_module_name = "mypackage." + "mymodule"

# The file gets executed upon import, as expected.
mymodule = importlib.import_module(full_module_name)

# Then you can use the module like normal
mymodule.func1()
mymodule.func2()

Conclusion

You should now know how to dynamically import modules using a module name stored in a string.

Reference links