Question

I’m writing a python file mylib.py

I’d like mylib.py to do something based on sys.argv if it’s being executed as a script. But if it’s imported from some other script, I don’t want it to do that.

How can I tell if my python file is being imported or it’s a main script?

(I’ve seen how to do this before, but I forgot.)

Answer 1

if __name__ == '__main__':
    # this was run as a main script

Here is the documentation on __main__.

Usually this code is placed at the bottom of a module, and one common way to keep your code clean is to create a main() function that does all of the work, and only call that function inside of the conditional.