Python imports from subfolders

Question

I am attempting to grade some python submissions that are in separate folders for each student. To do this, there is a function, say f() which I want to run. I understand that if my current path is the same as the one where the file is located, I can simply do

import filename
filename.f()

However, are there better ways? For instance, let's say the directory structure is as follows:

main.py
student/run_this.py

I know that if there is a "__init__.py" file in the student folder, I can just type

import student.run_this

However, without that file, it doesn't work.

Some similar questions I found were

• Import module from subfolder
• How to do relative imports in Python?
• http://www.daniweb.com/software-development/python/threads/192000/import-from-a-subdirectory-of-a-directory-on-pythonpath

but none of these gave particularly satisfying answers.

• eazar001: So what exactly is your issue with the __init__.py file?
• Martijn Pieters: You add the student folder to your path, then import run_this. That's what the other answers tell you to do, what did you try that didn't work?
• Viknesh: It's not that it didn't work as much as it didn't seem elegant. Or at least, adding _init_.py's seems pretty offputting to me - it seems immoral to modify the file structure to access subfolders. For changing the path, I read that was bad practice, but it does seem like a reasonable solution.

Answer 1

create an __init__.py module inside the folder student which should contain

from . import *

You can then call any modules from student folder to its parent folder modules as

import student.module.py

If you post any other errors you are facing, we can help further.

• Viknesh: Do you think you could explain (or link me to material) explaining why _init_.py's are required? That did end up working, but I'm a bit confused about what the design logic is
• Mathan Kumar: __init__.py is just as simple as class inheritance logic in c++ or python. When the python looks at a folder it does not includes all the modules available in it. If u specify the functions to be done when python enter into a class at __init__ function, it understands well. here we are just importing the necessary or all modules when python encounters a folder using __init__.
• George Willcox: This answer is the only one that I could find to answer the problem that I had, thanks @MathanKumar !