Question

I am trying to create a piece of code in Python 3 which allows the user to choose between several options. I have tried this several ways but none of them seem the right method to do so.

Example Attempt:

usr_input = input("Input: ")
while (usr_input != '1') | (usr_input != '2'):
    if usr_input == '1':
        search()
    elif usr_input == '2':
        sys.exit()

The problem with this is that the script hangs after entering an incorrect command.

Can anyone give me the correct way to do this?

Answer 1

There are a few things wrong here.

Firstly, you only get usr_input once, outside the loop. If it’s not a correct choice, you don’t give the user the change to correct their choice: you simply loop. You’ll need to do the input within the loop.

Secondly, your boolean condition is wrong. It is the equivalent of saying “x is not a OR not b”, which is always true, since even if it is a it is still not b. A better way of saying it is not in ['1', '2'].

Putting these together:

usr_input = ''
while usr_input not in ['1', '2']:
    usr_input = input("Input: ")
    ... etc...