Roman to Decimal-converter

Python based Roman to Decimal converter

Simple Knowledge

Roman numerals are a numeral system that originated in ancient Rome and remained the usual way of writing numbers throughout Europe well into the Late Middle Ages. Numbers in this system are represented by combinations of letters from the Latin alphabet.

The decimal numeral system is the standard system for denoting integer and non-integer numbers. It is the extension to non-integer numbers of the Hindu–Arabic numeral system. The way of denoting numbers in the decimal system is often referred to as decimal notation.

Python Code

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  def encoder(num):
    roman,s,decimal= ["M", "CM", "D", "CD", "C", "XC", "L", "XL", "X", "IX", "V", "IV", "I"],"",[1000,900,500,400,100,90,50,40,10,9,5,4,1]
    for i in range(13):
           while num >= decimal[i]:
                  num -= decimal[i]
                  s += roman[i]
    return s

def decoder(r):
    k=r
    if r=="":return "Don't leave the input blank"
    roman,s= {"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},0
    while r!="":
        if r[:2] in roman:a,r=r[:2],r[2:]
        elif r[0] in roman:a,r=r[0],r[1:]
        else: return "Enter proper Decimal/Roman number as input"
        s+=roman[a]
    return s if encoder(int(s))==k else "Not a valid Roman Numeral"
    
a=input()
try:print(encoder(int(a)))
except:print(decoder(a.upper())) 

Contributing

Contributions are always welcome!