How to fix "ImportError: No module named ..." error in Python?
PythonPython Problem Overview
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 Solutions
Solution 1 - Python
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 $PYTHONPATH.
Solution 2 - Python
Do you have a file called __init__.py in the foo directory? If not then python won't recognise foo as a python package.
See the section on packages in the python tutorial for more information.
Solution 3 - Python
A better fix than setting PYTHONPATH is to use python -m module.path
This will correctly set sys.path[0] and is a more reliable way to execute modules.
I have a quick writeup about this problem, as other answerers have mentioned the reason for this is python path/to/file.py puts path/to on the beginning of the PYTHONPATH (sys.path).
Solution 4 - Python
Here is a step-by-step solution:
- Add a script called
run.pyin/home/bodacydo/work/projectand edit it like this: > import programs.my_python_program > programs.my_python_program.main()
(replace main() with your equivalent method in my_python_program.)
2. Go to /home/bodacydo/work/project
- Run
run.py
Explanation:
Since python appends to PYTHONPATH the path of the script from which it runs, running run.py will append /home/bodacydo/work/project. And voilà, import foo.tasks will be found.
Solution 5 - Python
Example solution for adding the library to your PYTHONPATH.
-
Add the following line into your ~/.bashrc or just run it directly:
export PYTHONPATH="$PYTHONPATH:$HOME/.python" -
Then link your required library into your ~/.python folder, e.g.
ln -s /home/user/work/project/foo ~/.python/
Solution 6 - Python
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
Solution 7 - Python
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