How to python packages

how-to-python-packages.md

Setting up custom python packages

I know of one or more reported cases where python imports failed. Because python packages are arranged with reference to the file system structure, running a module that imports a package that is one-level up in the file hierarchy results in an ImportError.

This error can be resolved in any of the following ways:

1. Export $PYTHONPATH variable in your terminal

   export PYTHONPATH=.

   Check out this Enthought article about other alternatives.

2. Programmatically append the module's base path to sys.path

   import sys
   
   sys.path.append('./../')

3. Use Path entry finders ✔️

   While rambling about trying to run a module that imports a name from another module, I came upon a documentation about Path entry finders in the packages section of python docs

   Simply set __path__ to a list or tuple of paths where python can lookup modules.

   For my example package in this repository, I set __path__ = ['./../'] in the module I that intend to run.

   python3 one/b.py
   two

See an example package on using Path entry finders

Thanks. This helps.
Just to add to what you have from what I found on stackoverflow, If you just want to run the file, you could run it with the -m flag.

Python3 -m package.file.py

or you can add this at the top of the file

import sys
import os

 PACKAGE_PARENT = '..'
 SCRIPT_DIR = os.path.dirname(os.path.realpath(os.path.join(os.getcwd(), os.path.expanduser(__file__))))
 sys.path.append(os.path.normpath(os.path.join(SCRIPT_DIR, PACKAGE_PARENT)))

or just add this

import sys
sys.path.append('.')

This also has some useful tip, I have not tried it yet though, using a main.py file at the root of the project. https://docs.python.org/3/library/__main__.html