That relative imports hack for Python scripts

I need to write this down so I don’t forget it again. I’ve been struggling with “relative imports” in Python projects in VS Code. Here’s the problem.

The problem

Say I’m working on a Python project in VS Code. The project is in early stages and my file/folder structure looks something like this:

project/
    my_package/
        __init__.py
        my_module1.py
        my_module2.py
    experimental/
        experiment1.py
        experiment2.py
    main.py

The idea is to put some of the code required for main.py into a custom package my_package. While working on the package, I might want to try a few things out. That’s what the scripts in experimental/ are there for. I’m keeping them in a sub-folder so I can easily .gitignore them, and also to keep the main project folder clean.

Obviously, I want to import things from my_package into the experimental scripts. Naively, I tried this:

experiment1.py (not working!)

import ..my_package
from ..my_package import my_module1

While typing this, VS Code does not complain and it feels like it should work. After all, the double dorts .. indicate passage to the parent directory, which is the project root directory in this case and where my_package lives. However, when I hit the “play button” in the VS Code tab for experiment1.py, say, I get this error in the terminal:

ImportError: attempted relative import with no known parent package

I’m not going to get into why this doesn’t work. Instead I’ll go straight to a quick and dirty solution.

A quick-and-dirty solution

One solution is to manually instruct the Python interpreter where to look for packages and modules. In this case it needs to look in the project root directory while it’s running the script in the experimental/ folder. Here’s a way to do this:

experiment1.py (working!)

# Import the needed tools
import sys
from pathlib import Path
# Add project root to `sys.path` and...
sys.path.append(str(Path(__file__).resolve().parents[1]))

# ...and proceed as before without `..`
import my_package
from my_package import my_module1

I must have looked this up three to five times now. I’m still not sure if I’ll be able to remember it next time. But at least I know where to look now…

And yes, I’ve read that this is not good practice and should never be used in production code. But it seems to be fine for my experimental purposes.