python-crash-course/lesson_1/launching_python_file.py

"""
How to launch a python script, the right way
"""

# This is a very short introduction into the correct way of launching a python script.
# There's only 1 correct way of doing this, shown below.

import os

def main() -> None:
    print("Hello world!")
    
if __name__ == "__main__":
    main()
    
# In short a python script can be devided in 3 parts.
# Imports, definitions, directly executable.
# Only your main file should contain these 3 parts/sections. Any imported file should only contain the first 2
# parts. This prevents you from running a file that's only supposed to be imported, directly from terminal.
# Your main file must follow this setup. Failing to do so, will give you issues further down the path.

# The overall purpose of this setup is that the file you execute with python, is called "__main__" and
# any other files is called by their import name.

# Any code definitions are not executed until you actually call the function/method.