Using a function to validate user input as a letter

Asked Sep 09 '16 at 14:04

Active Sep 09 '16 at 14:12

Viewed 38 times

I am trying to ensure that whenever the user inputs a value, it is a letter. I created a function, which seems to work fine, when debugging, but the user_input is not returning the correct value in the function. It returns the invalid value that was entered into the function. Do I need to create a new variable in this function and return it instead? Or is there a better way to validate that an input is a letter. I've read about Value exception, but I thought this way would work fine as well.

def validate_input(user_input):
    while True:
        if user_input.isalpha():
            return False
        else:
            user_input = input("invalid selection, try again ")


user_guess = input("What is your guess? ")
validate_input(user_guess)

If there is a more efficient way, or a better Pythonic way, to do this, please let me know. Thanks in advance.

asked Sep 09 '16 at 14:04

Shannon Rogers

2

`return user_input` rather than `False` ? – Chris_Rands Sep 09 '16 at 14:08
why you return False instead of True or the `user_input`?? – Copperfield Sep 09 '16 at 14:08
How can you tell *what* `validate_input` is returning? – Scott Hunter Sep 09 '16 at 14:08
str.isalpha() is the solution – Humbalan Sep 09 '16 at 14:09
3

@Humbalan: That is already in the code; the problem is the code around it. – Scott Hunter Sep 09 '16 at 14:10
You say this function doesn't return the "correct value." What do you expect it to actually do? – TigerhawkT3 Sep 09 '16 at 14:15
`return user_input`? – David Zemens Sep 09 '16 at 14:20
@Chris_Rands, yeah, I have tried returning user_input rather than false, and I still end up returning the invalid input selection that was first entered. – Shannon Rogers Sep 09 '16 at 14:20
as you want only a letter, also check for `len(user_input)==1` – Copperfield Sep 09 '16 at 14:29
@Copperfield thank you – Shannon Rogers Sep 09 '16 at 14:37
@TigerhawkT3 thank you for the duplicate link. I corrected the function by just calling the prompt in the parameter, and creating a variable to store the input in the function, and then returning it. I just didn't understand why a parameter (variable) that I called in the function wouldn't return the correct value, even if I set that parameter called in equal to the input. But thank you – Shannon Rogers Sep 09 '16 at 16:01

Using a function to validate user input as a letter

0 Answers0