Python - Module Not Found

Question

I am a beginner with Python. Before I start, here's my Python folder structure

-project
----src
------model
--------order.py
------hello-world.py

Under src I have a folder named model which has a Python file called order.py which contents follow:

class SellOrder(object):
    def __init__(self,genericName,brandName):
        self.genericName = genericName
        self.brandName = brandName

Next my hello-world.py is inside the src folder, one level above order.py:

import model.order.SellOrder

order = SellOrder("Test","Test")

print order.brandName

Whenever I run python hello-world.py it results in the error

Traceback (most recent call last):
  File "hello-world.py", line 1, in <module>
    import model.order.SellOrder
ImportError: No module named model.order.SellOrder

Is there anything I missed?

Solution 1

All modules in Python have to have a certain directory structure. You can find details here.

Create an empty file called __init__.py under the model directory, such that your directory structure would look something like that:

.
└── project
    └── src
        ├── hello-world.py
        └── model
            ├── __init__.py
            └── order.py

Also in your hello-world.py file change the import statement to the following:

from model.order import SellOrder

That should fix it

P.S.: If you are placing your model directory in some other location (not in the same directory branch), you will have to modify the python path using sys.path.

Solution 2

If it's your root module just add it to PYTHONPATH (PyCharm usually does that)

export PYTHONPATH=$PYTHONPATH:<root module path>

for Docker:

ENV PYTHONPATH="${PYTHONPATH}:<root module path in container>"

Solution 3

you need a file named __init__.py (two underscores on each side) in every folder in the hierarchy, so one in src/ and one in model/. This is what python looks for to know that it should access a particular folder. The files are meant to contain initialization instructions but even if you create them empty this will solve it.

Solution 4

You need to make sure the module is installed for all versions of python

You can check to see if a module is installed for python by running:

pip uninstall moduleName

If it is installed, it will ask you if you want to delete it or not. My issue was that it was installed for python, but not for python3. To check to see if a module is installed for python3, run:

python3 -m pip uninstall moduleName

After doing this, if you find that a module is not installed for one or both versions, use these two commands to install the module.

• pip install moduleName
• python3 -m pip install moduleName

Solution 5

It's easier if you use this code

python3 -m module.sub_module

For example:

python3 -m entrypoint.settings

View more solutions

Comments

[user962206]

what should be the contents if init.py?

[Padraic Cunningham]

docs.python.org/2/tutorial/modules.html#packages

[miraculixx]

__init__.py can be empty or can contain code. it is common for projects to expose their primary / public classes at the package level. In your case you could add from model.order import SellOrder so that other code can do from project import Sellorder instead of from project.model.order import SellOrder.

[miraculixx]

also it's considered good practice not to have a src directory. that makes sense too because if you import your code somewhere else you should be able to import project.model and not project.src.model.

[Timo]

In src, init.py is not needed, see @Rafazz`s answer

[iyop45]

This is not what the question is asking

[Verma Aman]

Well, this helped me. Those modules were working through PyCharm but when I ran my program through Terminal it showed ModuleNotFoundError and this solution fixed my problem.

[wovano]

That's why you should never use #!/usr/bin/python but #!/usr/bin/env python (or #!/usr/bin/env python3 for Python3, or possibly #!/usr/bin/env python3.8 for a specific version). This will also work when using virtual environments, while the first form won't.

[Walker Sutton]

@iyop45 damn, you're right

[demberto]

Thank you so much for this :)

[Guy]

Very late to this thread, but I have the exact same structure as above, and using the solution above, I still can only run my program (locust -f src\main.py ...) if I use from src.module.submodule import main. Even with init.py in place. Maybe my cwd should be inside src?

[Dekriel]

this doesn't seem to be working. I have __init__.py in every folder but it still cannot be imported. Pycharm didn't show up with any errors, but the terminal kept showing up errors.

[Eduardo Reis]

For some reason it works when I run the python file. But when executing the same commands in the interactive mode, it does not work. Very intriguing.