Why is Python telling me variable is local not global?

Joined
Jul 20, 2023
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Its telling me that user_score and comp_score is a local variable.
Im using Pycharm.

Exact Error: Unresolved reference 'user_score'
File "/home/mattyp77/PycharmProjects/RockPaperScissor/main.py", line 55, in battle
user_score += 1
UnboundLocalError: local variable 'user_score' referenced before assignment

Also what is this about?
Local variable 'user_selection' might be referenced before assignment

Python:
import time
import random
import os


def clear_screen():
    # Check if the operating system is Windows
    if os.name == 'nt':
        os.system('cls')  # For Windows
    else:
        os.system('clear')  # For other platforms like macOS and Linux


# MATCHES USERS MENU SELECTION TO ROCK, PAPER, OR SCISSOR
# THEN CALLS COMPUTER SELECTION FOR MATCH UP AND BATTLE
def match(user_selection):
    user_selection -= 1
    if user_selection == 3: exit()
    print('    YOU:\n', tool[user_selection], '\nVS', end='')
    for _ in range(4):
        print('.', end='')
        time.sleep(1)
    computer_play(user_selection)


def computer_play(user):
    comp = random.randint(0, 2)
    print('\n   COMPUTER: \n', tool[comp])
    battle(user, comp)


def battle(user, comp):
    # ROCK = 0 : PAPER = 1 : SCISSOR = 2
    print(user, ' ', comp)
    if user == comp:
        print("You are tied")
    elif user + 2 == comp or user - 1 == comp:
        print(f'You WIN. {rck_ppr_scssr[user].upper()} beats {rck_ppr_scssr[comp].upper()}')
        user_score += 1
    else:
        print(f'Computer WINS. {rck_ppr_scssr[comp].upper()} beats {rck_ppr_scssr[user].upper()}')
        computer_score += 1
    print(f'Score: \n You: {user_score} \n Computer: {computer_score}')


def main_menu():
    while True:
        try:
            clear_screen()
            print(' ' * 40, 'Rock Paper Scissor\n')
            print('Enter your selection: \n1. Rock \n2. Paper \n3. Scissor\n4. Quit \n')

            user_selection = int(input(': '))
            if user_selection not in range(1, 5):
                clear_screen()
                print('Select a number between 1 and 4')
                input('Press ENTER to continue ')
                continue
            break
        except:
            clear_screen()
            print('Please enter only digits')
            input('Press ENTER to continue ')
            continue
    match(user_selection)


# ______________MAIN BODY _________________
go_again = 'y'
rck_ppr_scssr = ('rock', 'paper', 'scissor')
tool = ['ROCK', 'PAPER', 'SCISSOR']
global user_score; user_score = 0
global computer_score; computer_score = 0

# THIS IS FOR FILES I CREATED WITH ASCII ART. FOR SIMPLICITY I JUST CREATED THE
# tool [] LIST IN ITS PLACE
#for x in rck_ppr_scssr:
#    f = open(f'{x}.x', 'r')
#    tool.append(f.read())
#    f.close()

while go_again in ['y', 'yes']:
    main_menu()
    go_again = input('Keep playing? (Y/N): ').lower()
 
Last edited:
Joined
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Use the global keyword inside function (def)

[ on-line ]
Python:
def battle(user, comp):
    global user_score, computer_score

  1. When You Really Need Global Variables:
    There are situations where you need multiple functions to access and/or modify the same global variable. For example, a global variable might store configuration settings or data that is used in different parts of the program.

  2. Updating Global Variables Inside Functions:
    If you need to change the value of a global variable within a function, use global to indicate that you are working with the global version of the variable.

  3. Preserving a Reference to an Object:
    If you are working with mutable objects such as lists or dictionaries and want to modify their contents within a function, you can use global to maintain a reference to the global object.
 
Joined
Jul 20, 2023
Messages
56
Reaction score
2
Use the global keyword inside function (def)

[ on-line ]
Python:
def battle(user, comp):
    global user_score, computer_score

  1. When You Really Need Global Variables:
    There are situations where you need multiple functions to access and/or modify the same global variable. For example, a global variable might store configuration settings or data that is used in different parts of the program.

  2. Updating Global Variables Inside Functions:
    If you need to change the value of a global variable within a function, use global to indicate that you are working with the global version of the variable.

  3. Preserving a Reference to an Object:
    If you are working with mutable objects such as lists or dictionaries and want to modify their contents within a function, you can use global to maintain a reference to the global object.
Cool thanks. What do you think of the code? Any criticism?
 
Joined
Sep 21, 2022
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"What do you think of the code? Any criticism?"

Too long.

A simple game only needs a simple program.

I'd guess 25 lines.

Just my opinion.
 

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