Python - input control

Question

I have problem with users input control in one function in Python 3.4.

def input_name (*args):
    name_output = ""
    name_input = input ("Give first name: ")
    if name_input.isalpha() and name_input[0].isupper() == True:
        name_output += name_input
        return (name_output)
    else:
        print ("Wrong, do it again")
        input_name ()

name = input_name()
print(name.lower())

I am trying to catch users wrong input - so the name must be alphabetical and first letter must be uppercase. In future code I will create users login name with lowercase letters, so I am trying to print users name with small leters for login name. And there is problem.

When I type name firs time well, it's ok
When I type first time name with 1 lowercase letter (name) and then I write it correctly (Name), it tells me Error, I don't understand why. Can you tell me, what is my mistake?

Thank you very much for showing the path. Mirek

The Error is "AttributeError:'NoneType' object has no attribute 'lower'". Cdonts answer is great and solved the problem and everything is working now, but I am learnin coding, so now I would like to know, if is possible to repair my way I post here. — Mirek M.
– Mirek M., Commented Sep 4, 2015 at 23:37
Thank you very much. I've got here better solution then was my and knowledge how to repair my code. — Mirek M.
– Mirek M., Commented Sep 4, 2015 at 23:43

cdonts · Accepted Answer · 2015-09-04 22:30:03Z

1

The error is caused by the last line. Since your input is wrong the first time, the function returns None, so name.lower() raises an exception. I wouldn't use recursion in this case.

def input_name():
    while True:
        name_input = input ("Give first name: ")
        if name_input.isalpha() and name_input[0].isupper():
            return name_input
        else:
            print ("Wrong, do it again")

name = input_name()
print(name.lower())

Hope it helps!

answered Sep 4, 2015 at 22:30

cdonts

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