How can you restrict user to only input alphabets in Python?

Question

I am a beginner trying to learn Python. First question.

Trying to find a way to ask users to input alphabets only. Wrote this but it doesn't work! It returns True and then skips the rest before continuing to the else clause. break doesn't work either.

Can someone point out why? I assume it's very elementary, but I'm stuck and would appreciate it if someone could pull me out.

while True:
    n = input("write something")
    if print(n.isalpha()) == True:
        print(n)
        break
    else:
        print("Has to be in alphabets only.")

`if n.isalpha() is True:` (or just `if n.isalpha():`) . you check the return value of `print` which is `None`.... — hiro protagonist, Jun 03 '21 at 05:14

score 1 · Answer 1 · answered Jun 03 '21 at 05:14

1

Your problem here is the print function. print does not return anything, so your if statement is always comparing None to True.

while True:
    n = input("write something")
    if n.isalpha():
        print(n)
        break
    else:
        print("Has to be in alphabets only.")

answered Jun 03 '21 at 05:14

Tim Roberts

48,973
4
21
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Thank you! I didn't expect such help in so short a time! thank you. – Zane Jun 03 '21 at 06:04

score 1 · Answer 2 · answered Jun 03 '21 at 05:14

1

Your statement should be if n.isalpha() == True:. print won't return anything and so the value is None. Then, you are comparing None with True

while True:
    n = input("write something")
    if n.isalpha() == True:
        print(n)
        break
    else:
        print("Has to be in alphabets only.")

answered Jun 03 '21 at 05:14

Wow! so swift and great! It works! Thank you so much! – Zane Jun 03 '21 at 06:04
Most Welcome @Zane – Jun 03 '21 at 06:04

score 0 · Accepted Answer · answered Jun 03 '21 at 05:18

0

I've fixed the bug, below is the updated code:

while True:
    n = input("write something: ")
    if n.isalpha() == True:
        print(n)
        break
    else:
        print("Has to be in alphabets only.")

answered Jun 03 '21 at 05:18

Cool Breeze

738
2
10
26

1

Thank you! I've been struggling on this for hours. So Happy! – Zane Jun 03 '21 at 06:05
This can be optimized by dropping the `== True` part. The if condition can be written as `if n.isalpha():`. – Matthias Jun 09 '21 at 08:50

score -1 · Answer 4 · answered Jun 03 '21 at 05:22

-1

Don't use print(n.isaplha()), it will be always True. Remove print() and use only n.isalpha()
Try this:-

while True:
    n = input("write something")
    if print(n.isalpha()) == True:
        print(n)
        break
    else:
        print("Has to be in alphabets only.")

answered Jun 03 '21 at 05:22

Dr. Strange Codes

359
2
15

`print` returns `None` (as most of the other answers point out). it will not *always be True* (what does that even mean?). – hiro protagonist Jun 03 '21 at 05:35
It won't return none. Try it: `a = 'Hi'` `print(a.isalpha())`, doesn't it return true? And sorry if I am still wrong – Dr. Strange Codes Jun 03 '21 at 05:38
what i mean is this: `a = print("something")`, then `a is None`. what you are printing in your example is the return value of `isalpha` (which is a `bool` indeed). – hiro protagonist Jun 03 '21 at 06:01
Ok understood and sorry! – Dr. Strange Codes Jun 03 '21 at 06:05
1

Thank you! I am so emancipated now... After hours of scratching my head! Thank you. – Zane Jun 03 '21 at 06:06
Thanks everybody! Blown away by some much enthusiasm in helping out a hapless newbie! Scared to post first question, but happy to have done it! Again extreme appreciation! – Zane Jun 03 '21 at 06:14
1

How is this code fifferent from the code in the question? – Matthias Jun 09 '21 at 08:53

How can you restrict user to only input alphabets in Python?

4 Answers4