How to break a Python while loop from a function within the loop

Question

while True:
    input = raw_input(\"enter input: \")
    result = useInput(input)

def useInput(input):
    if input == \"exit\":
        break   #return 0 / quit /          


        

Answer 1

You can raise an exception and handle it outside of while ... but that will likely result in some confusing code ...

def useInput(in_):
    if in_ == "exit":
        raise RuntimeError
try:
    while True:
        input = raw_input("enter input: ")
        result = useInput(input)

except RuntimeError:
    pass

It's MUCH better to just return a boolean flag and then break or not depending on the value of that flag. If you're worried that you already have something you want to return, don't fret -- python will happily let your function return more than one thing:

def func()
    ...
    return something,flag

while True:
    something,flag = func()
    if flag:
        break