helpers.py

# Python program to convert Roman Numerals
# to Numbers


def roman_to_decimal(roman):

    def value(r):
        # This function returns value of each Roman symbol

        if r == 'I':
            return 1
        if r == 'V':
            return 5
        if r == 'X':
            return 10
        if r == 'L':
            return 50
        if r == 'C':
            return 100
        if r == 'D':
            return 500
        if r == 'M':
            return 1000
        return -1

    roman = str(roman)
    res = 0
    i = 0

    while i < len(roman):

        # Getting value of symbol s[i]
        s1 = value(roman[i])

        if i + 1 < len(roman):

            # Getting value of symbol s[i+1]
            s2 = value(roman[i + 1])

            # Comparing both values
            if s1 >= s2:

                # Value of current symbol is greater
                # or equal to the next symbol
                res = res + s1
                i = i + 1
            else:

                # Value of current symbol is greater
                # or equal to the next symbol
                res = res + s2 - s1
                i = i + 2
        else:
            res = res + s1
            i = i + 1

    return res