Python – Import module outside directory

Modules are simply a python .py file from which we can use functions, classes, variables in another file. To use these things in another file we need to first import that module into that file. If the module exists in the same directory as the file, we can directly import it using the syntax import module_name. But if it exists in a different directory we cannot directly import it. In this article, we will discuss various ways in which modules can be imported from outside the directory.

Our directory tree will be as follows:

D :\projects\base
|__main.py   
|__app:
      |__modules
           |___mod.py

We have a folder named ‘base’ in D:\projects and in the base folder we have a folder named app. The base directory contains main.py from which we will import the module. The app folder contains another folder named modules which contains mod.py which is the module that needs to be imported.

We will keep the code of both files as simple as possible for a better explanation:

mod.py:

Now we will import the module mod.py and call its function hello in main.py using various methods. 

Method 1: Using sys.path.append()

The sys.path variable of the module sys contains the list of all directories in which python will search for a module to import. We can directly call this method to see the directories it contains. So for importing mod.py in main.py we will append the path of mod.py in sys.path so that for importing python searches mod.py in its directories and finds it to successfully import it. The code for this method will be:

Output:

hello Lazyroar!

Method 2: Using sys.path.insert().

As we have already discussed, sys.path contains the list of all directories that will be searched for the module. A better way is to insert the directory of the module at position 1 so that it is loaded with a higher priority which in turn helps in avoiding some name conflicts. The code of main.py for this method will be:

Output:

hello Lazyroar!

Method 3: Using the __init__.py

We can also import the module by first converting the directory where it exists as python package. To convert a directory to a python package we have to include a file __init__.py in that directory which can be left empty. When we add the file __init__.py we tell python that the directory is a package. After creating the __init__.py the directory tree will look like this:

D :\projects\base
|__main.py 
|__app:
|      |__modules
|          |___mod.py
|          |___init__.py

The way we call for the module in the import statement is we go from the app folder to the mod file and separate each path variable with a ‘.’ . Now for importing mod.py in main.py from this method the code in main.py will be:

Output:

hello Lazyroar!

Method 4: Using the import library

We can also import a module from an outside directory using the import library. For this, we will first have to import the importlib.util module. Then call the importlib.util.spec_from_file_location() method which takes 2 arguments file_name and file_path, which returns a value. This value will be used with importlib.util.module_from_spec() method to import a module with a specific name. Then we can use this specific name to call the functions, classes, variables of the module.

Output:

hello Lazyroar!