How to Dynamically Load Modules or Classes in Python

Python provides a feature to create and store classes and methods and store them for further use. The file containing these sets of methods and classes is called a module. A module can have other modules inside it.

Note: For more information, refer to Python Modules

Example: A simple example of importing a module is shown below in which, there are 2 files that are module.py and importing_mod.py in the same directory. The module.py file acts as a module to import_mod.py file.

module.py

import_mod.py file

Output

Hi! User_1 Welcome to GfG

Dynamically Loading Modules or Classes

The modules added in the above code are importing modules statically i.e in compile time. In Python we can import modules dynamically by two ways

• By using __import__() method: __import__() is a dunder method (methods of class starting and ending with double underscore also called magic method) and all classes own it. It is used to import a module or a class within the instance of a class. There is an example on this method given as follows, in which we will be importing a module dynamically. The module file is now modified as:

  module.py

  
  

  
  
  

  # class inside the module class Welcome:     def welcome(str):         print("Hi ! % s Welcome to GfG" % str)

  Dynamic_import.py

  
  

  
  
  

  class Dimport:     def __init__(self, module_name, class_name):         #__import__ method used         # to fetch module         module = __import__(module_name)            # getting attribute by         # getattr() method         my_class = getattr(module, class_name)         my_class.welcome('User_1')      # Driver Code   obj = Dimport("module", "Welcome")

  Output

  Hi! User_1 Welcome to GfG

• Using the imp module: Modules can be imported dynamically by the imp module in python. The example below is a demonstration on the using the imp module. It provides the find_module() method to find the module and the import_module() method to import it.

  Dynamic_import.py

  
  

  
  
  

  import imp import sys       # dynamic import  def dynamic_imp(name, class_name):            # find_module() method is used     # to find the module and return     # its description and path     try:         fp, path, desc = imp.find_module(name)                except ImportError:         print ("module not found: " + name)                try:     # load_modules loads the module      # dynamically ans takes the filepath     # module and description as parameter         example_package = imp.load_module(name, fp,                                           path, desc)                except Exception as e:         print(e)                try:         myclass = imp.load_module("% s.% s" % (name,                                                class_name),                                    fp, path, desc)                except Exception as e:         print(e)                return example_package, myclass        #  Driver code if __name__ == "__main__":     mod, modCl = dynamic_imp("GFG", "addNumbers")     modCl.addNumbers(1, 2)

  Output

  Hi! User_1 Welcome to GfG