Counter Variable "Not Assigned?"

Question

I am making a simple rock, paper, scissors game in python - and the counter variable comes up as an error neither me or my computer science can seem to place.

import random
options = ["R", "P", "S"]
userwin = 0
computerwin = 0
counter = 0

def RPS():
    counter = counter + 1
    computerchoice = random.choice(options)
    print ("It's round number", counter, "!")
    humanchoice = input ("Do you choose rock [R], paper [P] or scissors[S]?")

    if computerchoice == "R":
        if humanchoice == "R":
            print ("Rock grinds rock - it's a draw!")
        if humanchoice == "P":
            print ("Paper wraps rock - you win!")
            userwin = userwin + 1
        if humanchoice == "S":
            print ("Rock blunts scissors - you lost!")
            computerwin = computerwin + 1

    if computerchoice == "S":
        if humanchoice == "S":
            print ("Scissors strikes scissors - it's a draw!")
        if humanchoice == "R":
            print ("Rock blunts scissors - you win!")
            userwin = userwin + 1
            if humanchoice == "P":
                print ("Scissors cuts paper - you lost!")
                computerwin = computerwin + 1

    if computerchoice == "P":
        if humanchoice == "P":
            print ("Paper folds paper - it's a draw!")
        if humanchoice == "S":
            print ("Scissors cuts paper - you win!")
            userwin = userwin + 1
        if humanchoice == "S":
            print ("Paper wraps scissors - you lost!")
            computerwin = computerwin + 1

while userwin < 10 or computerwin < 10:
    RPS()

The error which comes up is

counter = counter + 1
UnboundLocalError: local variable 'counter' referenced before assignment

I haven't come across this error before - and am unsure how to fix it. Any ideas? Thank you!

Possible duplicate of [UnboundLocalError in Python](http://stackoverflow.com/questions/9264763/unboundlocalerror-in-python) — Mohammad, Nov 28 '16 at 12:38
Please fix the indentation of your code, it is unrunnable as written. — Rory Daulton, Nov 28 '16 at 12:39
As @mohammad said : counter is a variable in module scope, not accessible direclty from `RPS` function. You have to either define it as global or define it as a parameter of `RPS` function. — C.LECLERC, Nov 28 '16 at 12:39
inbefore : you gonna have the same problem with other variables. — C.LECLERC, Nov 28 '16 at 12:42

Joshua Bakker · Answer 1 · 2016-11-28T13:10:56.517

1

You can't assign global variables in a function, you need to do it like:

def RPS():
    global counter

    counter = counter + 1
    computerchoice = random.choice(options)

You have to do it for every variable that's defined outside the function.

edited Nov 28 '16 at 13:10

answered Nov 28 '16 at 12:47

Joshua Bakker

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`You can't access global variables in a function`, I think it should be `You can't assign global variables in a function`. – Mohammad Nov 28 '16 at 13:00

Counter Variable "Not Assigned?"

1 Answers1