How Can I Dynamically Import Python Modules Using Their String Names?

Dynamically Importing Modules Using String Module Names

In Python, it's possible to extend applications by importing modules dynamically. One application of this technique is executing commands from a string argument, allowing extensible modules without modifying the main code.

Using the __import__() function, you can import modules specified by their string names. However, for a more idiomatic approach, consider using the importlib module.

For Python 2.7 and 3.1 and later, importlib provides the import_module() function:

importlib.import_module(name, package=None)

This function imports the specified module, which can be referenced by its absolute or relative name. If the name is relative, the package argument should specify the anchor for resolving the name. For example:

my_module = importlib.import_module('os.path')

In the example provided, the goal is to import a command module based on a string argument. Using importlib, you can refine the code as follows:

import importlib
command = sys.argv[1]
try:
    command_module = importlib.import_module("myapp.commands." + command)
except ImportError:
    # Display error message

command_module.run()

This solution provides a more concise and idiomatic way to dynamically import command modules without modifying the core application code, enabling easy extensibility.

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