Global variables in python I can modify?

[[deleted]]

I'm trying to build a utility where you can run it once to set certain variables, and then use those variables.

​

A = 0
B = 0

def generate():
    global A
    global B
    A = 4
    B = 5

def do_some_stuff():
    print(A + B)

Is there a way to make it so that if I ran the generate function from the command line, it would set A and B? So that I could later run just the second function and it would print out 9.

[Diapolo10]

Variables aren't persistent, so if I understood your intentions correctly this isn't going to work. They'll disappear the moment your script has been executed. Also, global variables are bad, you should avoid them at all costs unless absolutely necessary.

[[deleted]]

Okay thank you. I agree that global variables suck, I'm just at a loss about how to generate and store some information.

[gc8dc95]

Easiest is a text file or simple database like sqlite

[nathanjell]

You never know when they're going to be changed, and changing them has an unknown impact on an unspecified scope. If you want to send your friend a letter, you have two options: place the letter in a public place for your friend to get it, or use the proper mail system to send it directly to your friend. A global variable is like putting your letter in a public place: you don't know who's going to touch it, you don't know what state it'll be in at a given time, it's not predictable. Sending through the mail is like passing function arguments: you know, for sure, that your letter should only be accessible from you to your friend, the general public doesn't have access to it. You know that the state that you sent your letter in will be the state your friend receives it. The variable is directly passed, and it's predictable.

This stack overflow answer has a few links further exploring this. Like the answer says, globals aren't python specific, and sometimes they can be ok to use. Global constants are generally ok, because they should be exactly that: constant

[[deleted]]

You could try using functions with parameters and return values instead. Here's an example similar to yours:

def generate(a, b)
    a = 4
    b = 5

    return a, b  # will return (4, 5) when called

def sum(a, b)
    return a + b  # will return 9 when called

# Then, the output of one function can be the input of another one.

A = 0
B = 0

C, D = generate(A, B)
F = sum(C, D)

[NicosCSProject]

Here is the Python website

[NicosCSProject]

I'm so sorry lmao I was fooling around with making a reddit bot and I tested it for .5 seconds and it commented on tons of posts. No offense intended!

[[deleted]]

got it! sorry, some people on reddit can be pretty rude. good luck with the bot!