Except error for a name

Question

I have a problem with a program I am making to do with an arithmetic quiz.when I enter a name the quiz should print the welcome message however if I enter a blank or a number then the programme should loop the question but tell the user that they have made an error. I used the try statement and the NameError statement to try and resolve this problem but when I use the function "except" and run it in idle it says that I have an invalid syntax.

here is the code i am trying to fix:

import random 
while True:
    try:
        UserName = input("What is your name:")
        except NameError:
            print ("The answer given does not compute!! Try again")
            continue
        else:
            break

        print(UserName," welcome to the Arithmetic Quiz.")

I have edited the code for the program, but still when I try to run it in Idle it highlights except and then says invalid syntax.

Can you add the error message? It looks like `except NameError:` is not aligned properly, at least in your example, it should be aligned with the try: statement it corresponds to. — Tom Myddeltyn, May 04 '16 at 21:53
@Natecat I have moved the indentation to the right place but I still get an error . Thanks — super123, May 04 '16 at 21:54
@busfault I have aligned the code properly but still not able to get it to work it just says that except is an invalid syntax — super123, May 04 '16 at 21:57
What exactly are you trying to prevent in the loop? An empty string? — OneCricketeer, May 04 '16 at 21:58
@super123 I am not as familiar with Python3, and I assume it is with the `print(...)` format, but can you have a space between `print` and `(...)` edit:"Though, that is not likely the issue since it is after the except. — Tom Myddeltyn, May 04 '16 at 21:59
Possible duplicate of [Asking user for input until they give valid response](http://stackoverflow.com/questions/23294658/asking-the-user-for-input-until-they-give-a-valid-response) — OneCricketeer, May 04 '16 at 22:00
@cricket_007 If the use enters a blank input for the name it should loop the question again. — super123, May 04 '16 at 22:03
@busfault when I run the code and put a blank input it shows the welcome message and does not loop the question? — super123, May 04 '16 at 22:07
@super123 That is because input isn't raising and exception. try running it from the interpreter. does `>>> UserName = input("What is your name:")` give you a NameError exception when you just press enter? or enter a number? this is unless, `input` is some other function that you have defined that raises a NameError? — Tom Myddeltyn, May 04 '16 at 22:11
A NameError has nothing to do with whether the input is a valid name of a human being. It indicates that a variable lookup has found no value for the variable. If you're getting such errors out of an `input` call, you're on Python 2 and you should be using `raw_input`. Python 2's `input` is essentially never a good idea. — user2357112, May 04 '16 at 22:15
@super123: Then that line can't raise a NameError. If you want to validate the name entered, you have to check the conditions you're interested in manually. — user2357112, May 04 '16 at 22:18

score 2 · Answer 1 · answered May 04 '16 at 22:12

2

You don't need a try-except to check for an empty string

while True:
    UserName = input("What is your name:")
    if not UserName:
        print("The answer given does not compute!! Try again")
        continue
    else:
        break
print(UserName," welcome to the Arithmetic Quiz.")

answered May 04 '16 at 22:12

OneCricketeer

179,855
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is there a way to make it so that if there was a blank space error or digit it would loop the question.@cricket_007 – super123 May 04 '16 at 22:21
I understand what you mean now so if the value checking is empty you don't use the try function @cricket_007 – super123 May 04 '16 at 22:22
For a digit, you could use `if UserName.isdigit()` to check if something more than spaces was entered you could check `if UserName.strip()` – OneCricketeer May 04 '16 at 22:32
Under stood do you know anybooks that have this info inside them please @cricket_007 – super123 May 04 '16 at 22:38
Don't know any books. All the python I learned was from reading the Python documentation online. – OneCricketeer May 04 '16 at 22:47
when i use the .strip() and enter letters it loops the question – super123 May 04 '16 at 22:51
Is there another way to stop the input of symbols with affecting the string input @cricket_007 – super123 May 04 '16 at 22:52
You could try `UserName.isalpha()` to check for all alphabetical characters. – OneCricketeer May 04 '16 at 22:55
Let us [continue this discussion in chat](http://chat.stackoverflow.com/rooms/111057/discussion-between-super123-and-cricket-007). – super123 May 04 '16 at 23:00

Tom Myddeltyn · Answer 2 · 2016-05-04T22:40:40.913

1

This is what the proper indentation should be for the try: except: else: block

import random 
while True:
    try:
        UserName = input("What is your name:")
    except NameError: 
        print("The answer given does not compute!! Try again")
        continue
    else:
        break
print(UserName," welcome to the Arithmetic Quiz.")

caveat (thanks cricket_007) this loop will never end. I had meant this comment to show how the try: indentation should have been for the OP.

edited May 04 '16 at 22:40

answered May 04 '16 at 22:05

Tom Myddeltyn

1,307
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1

This is the correct indentation, but the loop never exits – OneCricketeer May 04 '16 at 22:33
@cricket_007 I had meant it to only show what the indentation should be like for the OP. I guess I should have elaborated a little :-) thanks! – Tom Myddeltyn May 04 '16 at 22:41

Except error for a name

2 Answers2