Global variables and coding style recommendations

Question

This question is quite general but it's more for me to understand good coding practices in python...

I'd like to define a constant that I can use inside in any function without having to pass it as argument, and without the need to change it anywhere after its declared - maybe it'd be nice to make it impossible to change but not sure if i can do that.

What'd be the best way to do this, in terms of programming style (coding, name convention, etc.)

I.e., GLOBAL_CONSTANT='this_variable_will_not_be_changed'

My python code would have this form, is it good style as well?

#!/usr/bin/env python

import sys
import os

GLOBAL_CONSTANT='this_variable_will_not_be_changed'

def test():
    print GLOBAL_CONSTANT
    return 0

def main():
    test()
    return 0

if __name__ == "__main__":
    main()

Answer 1

Your code doesn't really do anything, so I guess it's fine! With regards to styling your code, refer to PEP 8 whenever you're in doubt.

• Global Variables

• Constants

With no more information than you've already given us, I'd have to say your conventions are ok.

Strictly adhering to PEP-8 isn't necessary however. The general consensus tends to be "Keep your code consistent". It can be confusing reading through a PEP-8 formatted file only to stumble into "blocks" of Java-esque or Hungarian notation code.

Answer 2

In 99% cases this is enough. But if you extremely need this value really constant you can check this

BTW: It will be hard way to learn Python by reflecting everything in other languages. Try forget past. Learn think Pythonic.