Python - working with fractions

# Add, Subract, Multiply or Divide Fractions with python
 
# use the built in python Fraction module
from fractions import Fraction
 
print("Enter two fractions.")
 
# Get the two fractions
a = Fraction(input("Enter the first fraction: "))
b = Fraction(input("Enter the second fraction: "))
 
print("Add: ", a + b)
print("Subtract: ", a - b)
print("Multiply: ", a * b)
print("Divide: ", a / b)
 
# my output:
## Enter two fractions.
## Enter the first fraction: 1/2
## Enter the second fraction: 2/5
## Add:  9/10
## Subtract:  1/10
## Multiply:  1/5
## Divide:  5/4
 
 

Python - Roman Numeral to Number Generator

# Convert a roman numeral to a number. 
# 
# If you are interested in roman numerals check out my other post  
# python script that takes a number and generates a roman numeral 
# 
# For a life time of knowledge checkout: 
# http://en.wikipedia.org/wiki/Roman_numerals 
# 
 
 
 
def ConvertRomanNumeralToNumber(roman_numeral):
    number_result = 0
    
    roman_numerals = {
        1:"I", 4:"IV", 5:"V", 9:"IX",
        10:"X", 40:"XL", 50:"L",
        90:"XC", 100:"C", 400:"CD",
        500:"D", 900:"CM", 1000:"M"}
 
    # Iterate through the roman numerals.  But you see here that I sort them to 
    # get the largest string size first: "CD" comes before "I" 
    for numeral_value in sorted(roman_numerals,
                                key=lambda roman: len(roman_numerals[roman]),
                                reverse=True):
        keep_converting = True
        while keep_converting:            
            if roman_numeral.find(roman_numerals[numeral_value]) != -1:
                number_result += numeral_value
                roman_numeral = roman_numeral.replace(roman_numerals[numeral_value], "", 1)
            else:
                keep_converting = False
                
    return number_result
 
 
print(ConvertRomanNumeralToNumber("MCDXLIV"))
print(ConvertRomanNumeralToNumber("MMMDCCCLXXXVIII"))
print(ConvertRomanNumeralToNumber("MMMCMXCIX"))
 
# my output: 
#  1444 
#  3888 
#  3999 
 
 

Python - Roman Numeral Generator

# Convert a number to a roman numeral. 
# 
# If you are interested in roman numerals check out my other post to convert roman numerals back to numbers 
# python script that takes roman numerals and generates numbers. 
# 
# To increase your life time of knowledge read up on roman numerals: 
# http://en.wikipedia.org/wiki/Roman_numerals 
 
 
def ConvertNumberToRomanNumeral(number):
    roman_numeral_result = "" 
    
    # Roman numeral dict. Place approved roman numeral key:value pairs 
    # in the dict and they will be used. 
    roman_numerals = {
        1:"I", 4:"IV", 5:"V", 9:"IX",
        10:"X", 40:"XL", 50:"L",
        90:"XC", 100:"C", 400:"CD",
        500:"D", 900:"CM", 1000:"M"}
 
    # Iterate from highest to lowest through the roman numerals. 
    for numeral_value in sorted(roman_numerals.keys(), reverse=True):
 
        # Continue replacing large roman numerals while the number is 
        # high enough. 
        while (number >= numeral_value):
            # Build the Roman Numeral string. 
            roman_numeral_result += roman_numerals[numeral_value]
            # Decrease the working number by the roman numeral value just 
            # added to the roman numeral result. 
            number -= numeral_value
 
    return roman_numeral_result
 
 
print(ConvertNumberToRomanNumeral(1444))
print(ConvertNumberToRomanNumeral(3888))
print(ConvertNumberToRomanNumeral(3999))
 
# my output: 
#  MCDXLIV 
#  MMMDCCCLXXXVIII 
#  MMMCMXCIX