How to iterate through dictionary to match key value to string value

Question

Im trying to solve roman numeral leetcode in python. here is my code

i tried multiple ways of comparing the dictionary to the key value and then each single character of the string to the dictionary but dont know how to put it in code.

class Solution(object):
    def romanToInt(self, s):
        """
        :type s: str
        :rtype: int
        """
        LETTERS = {"I": 1,"V":5,"X":10,"L":50,"C":100,"D":500,"M":1000}
        total = 0
        for key in LETTERS:
            if key == s[1:]:
                total += LETTERS[key]

        return total

Answer 1

You don't want to iterate through your keys but through the string to get converted. First change your loop to something like:

for symbol in s:
     total += LETTERS[symbol]

However there is an issue with roman numbers like IV being 4 and IX being 9 with such approach.