Dynamically Load Python Modules or Classes

Fri 21 December 2012 by Thomas Sileo

Or how to instantiate a Python class from a string using importlib.

There is an official Python module, importlib, that allows you to import any Python module from a string. You may need to install it if you run a Python version older than 2.7.

Loading dynamically a class with importlib is easy, first you have to actually load the module with import_module, and finally you can retrieve the class with getattr.

Here is a working function that takes a string like module.submodule.MyClass as argument and returns the class:

import importlib

def load_class(full_class_string):
    """
    dynamically load a class from a string
    """

    class_data = full_class_string.split(".")
    module_path = ".".join(class_data[:-1])
    class_str = class_data[-1]

    module = importlib.import_module(module_path)
    # Finally, we retrieve the Class
    return getattr(module, class_str)

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