How to fix "ImportError: No module named ..." error in Python?

user_257942 0
Viewed 572490

What is the correct way to fix this ImportError error?

I have the following directory structure:

/home/bodacydo
/home/bodacydo/work
/home/bodacydo/work/project
/home/bodacydo/work/project/programs
/home/bodacydo/work/project/foo

And I am in the directory

/home/bodacydo/work/project

Now if I type

python ./programs/my_python_program.py

I instantly get

ImportError: No module named foo.tasks

The ./programs/my_python_program.py contains the following line:

from foo.tasks import my_function

I can't understand why python won't find ./foo/tasks.py - it's there.

If I do it from the Python shell, then it works:

python
>>> from foo.tasks import my_function

It only doesn't work if I call it via python ./programs/my_python_program.py script.

python
7 Answers

Python does not add the current directory to sys.path, but rather the directory that the script is in. Add /home/bodacydo/work/project to either sys.path or $PYTHONPATH.

Ignacio_Vazquez-Abrams_208620

Do you have a file called __init__.py in the foo directory? If not then python won't recognise foo as a python package.

See the section on packages in the python tutorial for more information.

user_2064170

In my mind I have to consider that the foo folder is a stand-alone library. I might want to consider moving it to the Lib\site-packages folder within a python installation. I might want to consider adding a foo.pth file there.

I know it's a library since the ./programs/my_python_program.py contains the following line:

from foo.tasks import my_function

So it doesn't matter that ./programs is a sibling folder to ./foo. It's the fact that my_python_program.py is run as a script like this:

python ./programs/my_python_program.py

quamrana_48340

If you have this problem when using an instaled version, when using setup.py, make sure your module is included inside packages

setup(name='Your program',
    version='0.7.0',
    description='Your desccription',
    packages=['foo', 'foo.bar'], # add `foo.bar` here
user_34290150
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