One of the recurring feature of a script I am working on is asking the user to input Yes or No. To make the script as dummy-proof as possible, I want to make sure that any inputs other than 'Y', 'y', 'N', and 'n' are all rejected, and the user will be asked to re-enter a value. I wrote a function called test_yes_or_no to help me with this.
def test_yes_or_no(answer):
if answer in ('Y', 'y'):
return True
elif answer in ('N', 'n'):
return False
else:
return None
Here is an example where I use test_yes_or_no:
def main():
while True:
ans = raw_input("Yes or no? (Y/N) ")
if test_yes_or_no(ans) == True:
#do something
break
elif test_yes_or_no(ans) == False:
#do something
break
else:
print("Invalid answer. Please try again.")
I have many other similar do-while loops that also ask for new raw_inputs() until a valid input is found. (e.g. Make sure that the user enters one single digit) These do-while loops all look something like
while True:
if condition():
break
elif condition2():
break
elif condition3():
break
elif condition4():
break
....
As you can imagine, I ended up with many do-while loops like the example above nested on top of each other, and the code quickly became quite messy. Is there a more elegant way to make sure raw_input() returns valid option without writing while True: loops?
