Python – Should Constants Be All Uppercase?

coding-standardscoding-styleconventionspython

I am a Python programmer primarily who uses pylint for linting source code. I am able to eliminate all of the warnings except one: Invalid name for a constant. Changing the name to all caps fixes it, but am I really supposed to do that? If I do it, I find that my code looks ugly as most of the variables are constant (according to pylint).

Best Answer

You are probably writing code like this:

notes_director = argv[1]
chdir(notes_director)
files = glob('*.txt')
rand_file = choice(files)
with open(rand_file) as notes_file: 
    points = notes_file.readlines() 
    rand_point = choice(points)

You should move this code into a function:

def main():
    notes_director = argv[1]
    chdir(notes_director)
    files = glob('*.txt')
    rand_file = choice(files)
    with open(rand_file) as notes_file: 
        points = notes_file.readlines() 
        rand_point = choice(points)

# actually call the main function    
main()

Pylint assumes that code that actually does the work will be inside a function. Because you have this code at the top level of your code instead of inside a function it gets confused.

Generally speaking, it is better style to do work inside a function instead of at the top level. This allows you to better organize what you are doing and facilitates reusing it. You should really only have code performing an algorithm outside of a function in a quick and dirty script.

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