PyCharm error: 'No Module' when trying to

Question

I have written a module (a file my_mod.py file residing in the folder my_module). Currently, I am working in the file cool_script.py that resides in the folder cur_proj. I have opened the folder in PyCharm using File -- open (and I assume, hence, it is a PyCharm project).

In ProjectView (CMD-7), I can see my project cur_proj (in red) and under "External Libraries" I do see my_module. In cool_script.py, I can write

from my_module import my_mod as mm

and PyCharm even makes suggestion for my_mod. So far so good.

However, when I try to run cool_script.py, PyCharm tells me "No module named my_module"

This seems strange to me, because

A) in the terminal (OS 10.10.2), in python, I can import the module no problem -- there is a corresponding entry in the PYTHONPATH in .bashrc

B) in PyCharm -- Settings -- Project cur_proj -- Project Interpreter -- CogWheel next to python interpreter -- more -- show paths for selected interpreter icon, the paths from PYTHONPATH do appear (as I think they should)

Hence, why do I get the error when I try to run cool_script.py? -- What am I missing?

Notes:

• I am not declaring a different / special python version at the top of cool_script.py
• I made sure that the path to my_module is correct
• I put __init__.py files (empty files) both in my_module and in cur_proj
• I am not using virtualenv

Addendum 2015-Feb-25

When I go in PyCharm to Run -- Edit Configurations, for my current project, there are two options that are selected with a check mark: "Add content roots to PYTHONPATH" and "Add source roots to PYTHONPATH". When I have both unchecked, I can load my module.

So it works now -- but why?

Further questions emerged:

• What are "content roots" and what are "source roots"? And why does adding something to the PYTHONPATH make it somehow break?
• should I uncheck both of those options all the time (so also in the defaults, not only the project specific configurations (left panel of the Run/Debug Configurations dialog)?

Answer 1

This worked for me: Go to Run-> Edit Configuration-> Python -> FileName.py Under working directory, checl :Add source roots to PYTHONPATH

Answer 2

my_module is a folder not a module and you can't import a folder, try moving my_mod.py to the same folder as the cool_script.py and then doimport my_mod as mm. This is because python only looks in the current directory and sys.path, and so wont find my_mod.py unless it's in the same directory

Or you can look here for an answer telling you how to import from other directories.

As to your other questions, I do not know as I do not use PyCharm.

Answer 3

The solution for this problem without having to Mark Directory as Source Root is to Edit Run Configurations and in Execution select the option "Redirect input from" and choose script you want to run. This works because it is then treated as if the script was run interactively in this directory. However Python will still mark the module name with an error "no module named x":

When the interpreter executes the import statement, it searches for x.py in a list of directories assembled from the following sources:

1. The directory from which the input script was run or the current directory if the interpreter is being run interactively
2. The list of directories contained in the PYTHONPATH environment variable, if it is set.
3. An installation-dependent list of directories configured at the time Python is installed, in my case usr/lib/python3.6 on Ubuntu.

Answer 4

If your own module is in the same path, you need mark the path as Sources Root. In the project explorer, right-click on the directory that you want import. Then select Mark Directory As and select Sources Root.

I hope this helps.

Answer 5

The key confusing step that must be done is to recreate the run configuration for the source file that you're trying to execute, so that the IDE picks up the new paths.

The way that actually worked for me was to go to Run/Edit Configurations..., select the configuration for the file that you're trying to run on the left side, uncheck the "Add source roots to PYTHONPATH" box, save, and then go back and check the box and save. THEN it would work.

Answer 6

I was getting the error with "Add source roots to PYTHONPATH" as well. My problem was that I had two folders with the same name, like project/subproject1/thing/src and project/subproject2/thing/src and I had both of them marked as source root. When I renamed one of the "thing" folders to "thing1" (any unique name), it worked.

Maybe if PyCharm automatically adds selected source roots, it doesn't use the full path and hence mixes up folders with the same name.