python python-3.x import module python-import

Importing dynamically all modules from a folder

I know there is this question, but not only they're not working, it's not exactly what I want. I'm developing a racing game and want to load all tracks from a folder dynamically (They're stored as .py instead of .json). I don't want to know the names of the tracks, since users can mod/add them at will. I just want to import their data. So, for example:

>tracks 
>>track0.py
>>track1.py
>>track2.py
>>track3.py
>>track4.py

Inside each track, I have data like this:

track_ground_data = [
    [1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1],
    [1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1],
    [1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1],
    [1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1],
    [1, 1, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 1, 1],
    [1, 1, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 1, 1],
    [1, 1, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 1, 1],
    [1, 1, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 1, 1],
    [1, 1, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 1, 1],
    [1, 1, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 1, 1],
    [1, 1, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 1, 1],
    [1, 1, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 1, 1],
    [1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1],
    [1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1],
    [1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1],
    [1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1]
]

I need to import each track module like this:

loaded_tracks = [t for t in tracks] # Where tracks is the folder.

And then access a given track_ground_data like this:

loaded_tracks[0].track_ground_data

If I knew Python was going to be so harsh with its imports, I'd have used json instead .py.

Solution

Python does not automatically import submodules contained in a package. Hence import tracks only loads tracks/__init__.py.

However you can put code inside the __init__.py file that imports all the modules it finds in that directory.

For example putting something like this in the __init__.py:

import os
import importlib

for file in os.listdir(os.path.dirname(__file__)):
    mod_name = file.removesuffix(".py")
    if mod_name in ("__init__", "__pycache__"): continue
    importlib.import_module('.' + mod_name, package=__name__)

Should make your submodules available as tracks.trackX when importing only tracks.

Or you could use exec:

import os
import importlib

for file in os.listdir(os.path.dirname(__file__)):
    mod_name = file.removesuffix(".py")
    if mod_name in ("__init__", "__pycache__"): continue
    exec('import .' + mod_name)

A cleaner approach would be to use import hooks or implement your own custom module importer. There are multiple ways to do this using importlib see also sys.path_hooks