Python cannot find module in same folder

Question

I have truly tried my best to understand python imports, but it makes no sense to me. I know there's a million SO threads on this but none of them have helped me understand what's going on.

I have this simple structure:

project/
    run.py
    datasets/
        __init__.py
        config.py
        datasetA.py

datasetA.py:

from config import classes
dosomething()

run.py:

from datasets import datasetA

And when I execute run.py, I get ModuleNotFoundError: No module named 'config'. Why? I have tried to include

import datasetA
import config 

as well as

import .datasetA
import .config 

in __init__.py but it makes no difference. datasetA sees __package__ = datasets , so it I think it should see config. run.py sees __package__ = None . What am I missing?

Answer 1

Relative vs absolute imports

Your issue relates to the differences between relative and absolute imports. When you try to import config from datasetA , python looks in the root directory, in this case, project/ . To fix this, what you want to do is use a relative import in datasetA. See the difference between the following:

# project/datasets/datasetA.py

# Absolute import
from config import classes

# Python checks for an available import at the root of the project
# (e.g. project/ in this case) and fails as it does not exist

# Relative import
from .config import classes

# Python checks in the current directory
# (e.g. project/datasets/) and succeeds

You can read more about relative and absolute imports here