Value error storing user input Integer into an array in Python

Question

I'm creating an application for my programming class and I'm unable to get it to run properly. Essentially, the application should take 8 numbers from the user and store them in an array and then add those numbers. However, if the user does not provide a number, or press Q, the program should stop.

userNumberList = []
counter = 0
while counter < 8:

    try:
        userNumber = int(input("Welcome! Please provide numbers or press q to quit. "))
    except ValueError:
        print("Not a number. Closing application.")
        break
    else:
        if userNumber == 'q':
            break
        else:
            userNumberList.append(int(userNumber))
            counter += 1

print(sum(userNumberList))

This is the error I get when running typing a String instead of a number in the prompt:

userNumber = int(input("Welcome! Please provide numbers or press q to quit. "))
ValueError: invalid literal for int() with base 10:

I feel like we need a canonical question specifically about trying to convert the letter `q` to an int... — Aran-Fey, May 24 '18 at 22:15
Anyway, the code you posted doesn't throw that exception. Your indentation is wrong (the code throws a SyntaxError), and if I fix that then the ValueError is caught correctly. Please post a [mcve]. — Aran-Fey, May 24 '18 at 22:17
Please can you fix the indentation? I can't see why you'd get that error. Also, we can use a full traceback here. — roganjosh, May 24 '18 at 22:17
And use `raw_input` over `input`. Tested it out, works a treat. `userNumber = raw_input("Welcome! Please provide numbers or press q to quit. ")` — Lex, May 25 '18 at 00:57

score 2 · Accepted Answer · answered May 24 '18 at 22:41

Try this: Do not convert to int before checking to q.

userNumberList = []
counter = 0
while counter < 8:
    userNumber = input("Welcome! Please provide numbers or press q to quit. ")
    if userNumber == 'q':
        print("Entered command to quit!! closing the application")
        break
    else:
        try:
            userNumberList.append(int(userNumber))
            counter += 1
        except ValueError:
            print("Not a number. Closing application.")
            break
print(sum(userNumberList))

Thanks for the help! When I run it and type Q to quit or provide a String instead of an int, I get the error: `ValueError: invalid literal for int() with base 10: ` — , May 24 '18 at 22:46

score 0 · Answer 2 · answered May 25 '18 at 01:01

0

Don't cast the input to an int straight away. You're handling that when appending anyway.

And apprently input evaluates input as python code. Use raw_input instead. This answer may be helpful Python 2.7 getting user input and manipulating as string without quotations

userNumber = raw_input("Welcome! Please provide numbers or press q to quit. ")

Changing this line fixes the program.

answered May 25 '18 at 01:01

Lex

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This is not an answer. The question is tagged as Python3 and seemingly the code is Python3. `raw_input` is not defined in Python3. – Mr. T May 25 '18 at 06:11
@Mr.T its also tagged with `python`, the code 'works' with that line amended. Your comment might be friendly/helpful mentioning that `raw_input` was renamed to `input` in python3 – Lex May 25 '18 at 08:03

Value error storing user input Integer into an array in Python

2 Answers2