How can i ask for a valid input if the user does a wrong input?

Question

Value= input('what do you prefer 'a' or 'b'? : ')
I am trying to ask an user to input 'a' or 'b', but how can repeat the input question if he does a wrong input like 'c' , 'd', 1 or 2 etc whatever...
To elaborate:
If i run the code,
>>> What do you prefer 'a' or 'b'?: c
#if I don't raise an exception here the value becomes "value='c'".
Which i don't want..instead i want to ask the user to again input the correct value like,
>>>The value was incorrect enter again? :

Answer 1

I tried this:
While True:
value= input().upper()
If value!='a' and value!='b':
Continue
else:
Break

Print(value) #just to check

And its asking me to enter value even after i enter 'a' or 'b'

What's the problem mahnnn..

Answer 2

You need used 'and' instead 'or'

Answer 3

If an exception pops up, then you need to use 'try' and 'except' if there are no exceptions, you can create a condition 'if', 'elif' and 'else'

Answer 4

You could try a "while True" loop and check input. if input is ok, you leave while loop with break and go on with the program.

while True:
inp = input('please select "a" or "b"')
if inp in 'ab':
break
print('invalid input - try again')
print(f'input was {inp}')

Answer 5

Now that was silly one from me, 😂

Anyways, thanks a lot💯