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Jorge Ponti
Asked: 2020-08-01 12:34:58 +0800 CST 2020-08-01 12:34:58 +0800 CST

Return option to "if" condition in Python 3 by option entered from keyboard

  • 772

In a part of my code I ask a question on the screen. The question as an answer requires a "yes" or "no", but when they misspell or something else I would like the code to return and ask again until the user correctly enters the option.

What I am doing is the following:

print("RESPONDA con si o no")
clave=input()
if clave=="N" or clave=="NO" or clave=="no" or clave=="No" or clave=="n" or clave=="nO":
    print("ok")

Does anyone know how to fix this? I can come up with a whilethat is in the loop as long as it responds fine, ending this with a break.

python

4 Answers

  1. Best Answer

    You could solve it like this:

    while(True):
    print("RESPONDA con sí o no")
    clave=input()
    if clave.upper()=="N" or clave.upper()=="NO": 
        print("ok")
        break
    elif clave.upper()=="S" or clave.upper()=="SI":
        print("otro ok")    
        break
    • 3

  2. You don't need to use break. The condition of your whileis what will cause the loop to stop. You only need three lines for this:

    >>> clave = ''
>>> while clave.upper() not in ('N', 'NO', 'S', 'SI'):
...     clave = input('¿Quieres continuar? (S/N): ')
... 
¿Quieres continuar? (S/N): dasda
¿Quieres continuar? (S/N): cxxczxc
¿Quieres continuar? (S/N): n
>>>

    After the block whileyou can process what you need with the final result:

    if clave.upper() in ('S', 'SI'):
    # Procesar respuesta afirmativa
else:
    # Procesar respuesta negativa
    • 3

  3. One whileshould be able to:

    notCalculated = true
while(notCalculated):
    print("RESPONDA con si o no") 
    clave=input() 
    if clave=="N" or clave=="NO" or clave=="no" or clave=="No" or clave=="n" or clave=="nO": 
       print("ok")
       notCalculated = false

    I'm not a python expert but other languages ​​have a command called break` if python has it do:

    while(true) :
    print("RESPONDA con si o no") clave=input()
    if clave=="N" or clave=="NO" or clave=="no" or clave=="No" or clave=="n" or clave=="nO": 
        print("ok")
        break
    • 2

  4. Another option is to include the condition in the while, like so:

    key = ""
while (not(key=="N" or key=="no" or key=="No" or key=="n" or key=="nO")):
    print("Answer yes or no")
    key = input()
print("ok") #outside the loop

    As it is in @Julio's answer, you can skip some orwith , upper()so you make it case insensitive

    • 2