Python: Can nested function change global variables?

Question

# Generate a random number between 1 and 9 (including 1 and 9). Ask the user to guess the number, then tell them whether they guessed too low, too high, or exactly right. (Hint: remember to use the user input lessons from the very first exercise)

# Extras:

# Keep the game going until the user types “exit”
# Keep track of how many guesses the user has taken, and when the game ends, print this out.
import random
counter = True

tooHigh = "You've guess too high"
justRight = "You've guessed correctly!"
tooLow = "You've guessed too low"

def generatedNumber():
    genValue = random.randint(1,9)
    return genValue
def guessTheNumber():
    guessedNumber = input("Guess a number between 1 and 9: ")
    if guessedNumber in "0123456789":
        guessedNumber = int(guessedNumber)
        print(type(guessedNumber))
    else:
        guessedNumber = 0
    return guessedNumber

def makeFalse():
    counter = False

def guessesComparer(computerNumber, userNumber):
    if userNumber == 0:
        makeFalse()
    elif computerNumber == userNumber:
        print(justRight)
    elif computerNumber > userNumber:
        print(tooLow)
    elif computerNumber < userNumber:
        print(tooHigh)

def mainAction():
    computerNumber = generatedNumber()
    userNumber = guessTheNumber()
    guessesComparer(computerNumber, userNumber)

while (counter == True):
    mainAction()

I'm simply wondering how I would get a nested function to change a global variable or if it's possible? I wanted to end the while loop at the end when the user types "exit", but I don't know how to switch the "counter" variable to false. I know there's a much simpler way to do this if I start the code over and do it in a different way, but I'm just trying to become good enough to do it multiple ways.

Answer 1

Yes, you can assign values to globals in any function if you declare global X before any assignment to that name then any assignment X = Y rather than binding a function local assigns a value to the global.

But it would be better to make an object out of those functions and store the state as instance variables rather than global variables.