How to import a Python module given the full path?


It is a recurrent and routine task of file handling in Python where there are solutions for different tasks of file processing. One such scenario is where you are required to import a module from a certain location on your system. Python's has appropriate tools to provide for dynamically importing modules where their full path is accessible. Such provisions make Python coding exhibit the power of flexibility and modularity. In this article, we explore various different methods to import Python modules when given their full path; each method offering unique advantages for various use cases. Here, an attempt is being made to efficiently guide you through each method with stepwise explanations and real-world code examples. By the end of this article, you'll be equipped with the skill of dynamically importing modules from any desired location. Let us take a plunge into the world of importing Python modules by using their full path.

Understanding Importing Python Modules by Full Path

We begin by attempting to grasp the concept of importing Python modules by full path. Then we go on to discuss the code examples and their explanations. The Python interpreter usually searches for modules in certain directories as given in the sys.path list. However, modules can be dynamically imported from any location by managing the sys.path or making use of built-in functions and libraries.

Using importlib.util.spec_from_file_location()

In our very first example, there is a demonstration of using importlib.util.spec_from_file_location() to import a Python module by full path.

In this code snippet, a function import_module_is defined by_path(); it takes module_path as its argument. We give a custom name known as the module_name, for the module to be imported. We deploy importlib.util.spec_from_file_location() to make a module specification based on the provided file location. Next, we go on to make use of importlib.util.module_from_spec() to generate a module object from the given specification. At last, spec.loader.exec_module() is used to execute the module code, and the module is ready to be used.

import importlib.util

def import_module_by_path(module_path):
   module_name = "custom_module"  # Provide a custom name for the module

   spec = importlib.util.spec_from_file_location(module_name, module_path)
   custom_module = importlib.util.module_from_spec(spec)
   spec.loader.exec_module(custom_module)

   return custom_module

Using imp.load_source() (Deprecated in Python 3.4)

In the next example it is shown how to import a module by full path by using the imp.load_source() method that has been since deprecated.

Here, the same function import_module_by_path() is defined; however, we use the now defunct imp.load_source() method to import the module. Although this method works, it must be noted that it is deprecated in Python 3.4 and might be dropped in future Python versions. Therefore, it is recommended to use the importlib methods for better maintainability and compatibility.

import imp

def import_module_by_path(module_path):
   module_name = "custom_module"  # Provide a custom name for the module

   custom_module = imp.load_source(module_name, module_path)

   return custom_module

Using importlib.machinery.SourceFileLoader()

Here, there is utilization of an alternate method where importlib.machinery.SourceFileLoader() is used to import a module by full path.

We make use of importlib.machinery.SourceFileLoader() to make a loader for the module indicated by module_path. The loader's load_module() method is then used to import and load the module. This strategy provides an alternative way to import modules from certain locations.

import importlib.machinery

def import_module_by_path(module_path):
   module_name = "custom_module"  # Provide a custom name for the module

   loader = importlib.machinery.SourceFileLoader(module_name, module_path)
   custom_module = loader.load_module()

   return custom_module

Using runpy.run_path()

Finally, in this last example, we deploy runpy.run_path() to execute code from a file and obtain the resulting namespace.

We define the function import_module_by_path() at first. We then go onto use runpy.run_path() to execute the code in the specified file (as described by the module_path) and obtain the resulting namespace. This method has its use when you wish to evaluate and work with the code in the desired module.

import runpy

def import_module_by_path(module_path):
   module_namespace = runpy.run_path(module_path)

   return module_namespace

The act of importing Python modules by full path permits you to bring in functionality from modules located just about anywhere on your system, This enhances the flexibility and the modularity of the code. Considering the various methods like importlib.util.spec_from_file_location(), imp.load_source() (deprecated), importlib.machinery.SourceFileLoader(), or runpy.run_path(), we must be aware that each method offers unique advantages based on your project's requirements.

As you move on forward on your Python journey, you must recall that the skill to dynamically import modules opens up several possibilities. Such skills bring flexibility and power to your projects, enabling you to create more organized and modular codebases.

Updated on: 28-Aug-2023

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