Cannot load module with PYTHONPATH

Question

I have a project called library and in it I have 3 folders - user, book and main. There is a user_utility.py in user. So let's say the project folder is:

/User/me/Projects/library/user/user_utility.py
/User/me/Projects/library/book/book_utility.py
/User/me/Projects/library/main/main.py

Now, in /User/me/Projects/library/main/main.py I would like to write the import statement as:

from user.user_utility import UserUtility

What is the $PYTHONPATH variable that allows me to do so? I tried

EXPORT PYTHONPATH="/User/me/Projects/library

but it does not work and it threw

No module named user.user_utility

• John Gordon: To be an importable module, the directory must also contain a file named __init__.py.

Answer 1

Messing with PYTHONPATH really is the wrong approach to go forward here. Instead, turn your user and book folders into proper modules/submodules. For doing so, you need to add __init__.py -files to (both of) them, looking like this for example:

from user_utility import some_routine

In your example, this would be /User/me/Projects/library/user/__init__.py. Now you can import this routine from your main.py-file as follows:

from user import some_routine

For full reference, have a look at the python documentation, modules tutorial.

• bryan.blackbee: i'll take your answer. what i need to do is to only point to the project folder.

Answer 2

If you call main.py directly from the command line, you can set the environment variable at the beginning of the line:

 PYTHONPATH=/User/me/Projects/Library python main.py

Otherwise, you should be able to set that module lookup path with:

export PYTHONPATH=/User/me/Projects/Library

To verify, you can see your environment variables with:

env

Also, make sure to put the __init__.py inside the user folder.