Importing a Function from another module

Question

I want to import a function named ret() from a module called mainprog into another module named windw .

So I did it like this in the windw module:

from mainprog import ret

This is supposed to work right?
But there is an infinite loop in the mainprog module.
So, even without calling the function I imported, it just keeps loading forever when I try to run the windw module.

So I guess it runs the whole mainprog module when I import? I need help to avoid this.

Answer 1

You are doing fine, all you need to do is make the loop not execute unless you are running the code by itself What you need to do is add a

if __name__ == '__main__':
    while True: 

This will make your program work as before, but make it possible to import functions within your code

Answer 2

You must make sure that the file mainprog.py does not have anything besides definitions of functions, constants and a __main__ guard .

If you have anything else defined like so:

do_something()
def ret():
    ...

Be sure to convert it to:

def ret():
    ...
if __name == '__main__':
    do_something()