topic Import module - undefined global variable in Python Questions

Import module - undefined global variable

DonBarker — Mon, 04 Jun 2012 15:00:30 GMT

I thought I understood and fixed this problem: A variable defined in a module remains undefined after I import the module. Here is the simplified version.

The main script and the module are in the same folder/dir.

This is my module: mysettings.py


def main():

    myvar = "This is imported."

if __name__ == '__main__':
    main()

This is my script: irp.py:


import mysettings

def main():

    print myvar

if __name__ == '__main__':
    main()

Interpreter error:

NameError: global name 'myvar' is not defined

Can you tell me why?

Thanks,

Re: Import module - undefined global variable

MathewCoyle — Mon, 04 Jun 2012 15:15:09 GMT

You need to do something like this in your irp.py

mysettings.main()

When you import a module it isn't executed as the __main__ so it needs to be called by function if you have it setup that way.

Re: Import module - undefined global variable

DonBarker — Mon, 04 Jun 2012 15:20:23 GMT

Matthew,

Thanks for taking time to reply.

I'm a Python novice so don't understand how/where to use this in my script. Can you explain?

Re: Import module - undefined global variable

MathewCoyle — Sat, 11 Dec 2021 09:20:21 GMT

Your mysettings.py should be something along these lines, depending on what it does.

def main():

    myvar = "This is imported."
    return myvar

if __name__ == '__main__':
    main()

Your irp.py should be something like this.

import mysettings

def main():

    print mysettings.main()

if __name__ == '__main__':
    main()

Re: Import module - undefined global variable

DonBarker — Wed, 06 Jun 2012 15:54:00 GMT

Got it now. Thanks again for taking time to reply and explain.