User:Inductiveload/Integer to Roman numerals converter

Python

This function takes a (positive) integer and returns a string holding the Roman numeral of that number.

#!/usr/bin/env python 
# -*- coding: UTF-8 -*-

def roman_numerals(x):
#Returns an upper-case Roman Numeral string representation of a decimal integer, n

    numeral_chars = (('M', 1000),('CM', 900), ('D', 500), ('CD', 400),
                ('C', 100), ('XC', 90),  ('L', 50),  ('XL', 40), 
                ('X', 10),  ('IX', 9),   ('V', 5),   ('IV', 4), ('I', 1))
    #RN character groups for each value up to 1000 (past this requires overbar)
    
    roman_num = []#initialise the list of characters groups
    for chr, value in numeral_chars:#for each group
        (remainder,x) = divmod(x, value)#work out how many of that group are needed, and remove from n
        roman_num.append(chr*remainder)#add the right number of groups to the list
    result = ''#empty string to populate
    return result.join(roman_num)#add each character group to the string and return