Discussion on: Dead Simple Python: Project Structure and Imports

[Jason C. McDonald]

This structure should work:

src/
├── __init__.py
├── __main__.py
│
├── game/
│   ├── __init__.py
│   └── cards98.py
│ 
├── reinforced/
│   ├── __init__.py
│   └── rl_agent.py
│ 
├── supervised/
│   └── __init__.py
│ 
├── Readme.md
└── License.md

You need __init__.py under each directory that you want to use as a package.

Then, from rl_agent.py, you should be able to use this import:

from src.game.cards98 import GameCards98

[Grzegorz Krug]

I know it should work, but it does not. I got
__init__.py everywhere and __main.py__ in top level.
Do I need to run it with -m param? I am definitely missing something. I was running scripts from top level to combine modules, but It can get messy sometimes :P

This is my repo: Github Cards98

[Jason C. McDonald]

It shouldn't be messy. But, yes, you'd need to invoke your top-level package (not your top-level script.)

python3 -m src

By the by, I recommend renaming src to your project name, cards98, and then renaming the subpackage by the same name to something like game.

[Grzegorz Krug]

Yes, now it is working. python -m cards98
Well... but only for invoking top level in console. It does not work for normal execution, like clicking 2 times __main.py__ with mouse.
This also makes debugging and testing harder, cause I have to change it always in __main__.py. Where can I use it? I think it just complicates everything.

Thanks for help in understanding this

[Jason C. McDonald]

This is, to my knowledge, the official (and only) way to structure a Python project. There are two to create an executable file to start everything.

Option 1: Native Script

Many Python projects offer a Bash script (on UNIX-like systems) or a Windows .bat file that will run the python3 -m cards98 command. I see this a lot.

Option 2: Python Script

This is the method I'd recommend, as it's the most portable.

Outside of your top-level package, you can write a separate Python script, such as run.py or cards98.py, and then use that to execute your main function.

For example, in cards98/__main__.py, you can put this...

def main():
    # The logic for starting your application.

if __name__ == "__main__":
    main()

And then, outside of the cards98 package, create the file cards98.py, with the following:

#!/usr/bin/env python3
from cards98.__main__ import main
main()

To start your Python application, just double-click cards98.py.

P.S. Thanks for bringing up this situation. I realized I never addressed it in the book!