Check if an input is a valid roman numeral

Question

I got a program that converts Roman numerals to integers and vice versa. My problem is that I don´t really know how to create a function that checks if the user input is a v

Answer 1

Apart from the design problems that have already been pointed out, I'd like to just answer the question why your for-loop doesn't go through all the numerals

If the entries are considered valid by your code, then the loop goes into the elif clause where it calls romanToInt(numeral)and then break. There's your problem: break take that out.

Illustration: As soon as condition is met in this example, the loop will stop going through i in list

for i in list:
   # do something
   if condition:
       break # "Stop the innermost loop now!"