Simple Roman Number Converter


Hello and welcome, this is the first post on this blog and I would like to say thank you for coming by. We shall start with simple and useful a small python program “Roman Number Converter” (i used python 3). So, let’s start,

  • First, we gonna need Roman numbers
  • And make python dictionaries for decimals, tens, hundreds and thousands. (The largest number will be 3999. Feel free to extend as large as you want, just simply add more dictionaries )
  • Another dictionary for previous four dictionaries. Decimal contains only 1 digit,  Tens contains 2 digits, and so on…
decimals = { '0' : '', '1' : 'I', '2' : 'II', '3' : 'III', '4' : 'IV',
 '5' : 'V', '6' : 'VI', '7' : 'VII', '8' : 'VIII', '9' :'IX'}
tens = { '0' : '', '1' :'X', '2' :'XX', '3' :'XXX', '4' :'XL', '5' :'L',
 '6' :'LX', '7' :'LXX', '8' :'LXXX', '9' :'XC'}
hundreds = { '0' : '', '1' :'C', '2' :'CC', '3' :'CCC', '4' :'CD',
 '5' :'D', '6' :'DC', '7' :'DCC', '8' :'DCCC', '9' :'CM'}
thousands = { '0' : '', '1' : 'M', '2' : 'MM', '3' : 'MMM'}
NumLength = { 1 : decimals, 2 : tens, 3 : hundreds, 4 : thousands}

And, a function to handle query (input) number :

  1. Convert input number into a string and make a list.
  2. Loop through each digit and collect Roman number from the each of the dictionary.
  3. Fetch a value from the NumLength dictionary with list length (that make sure to collect a Roman number from the correct dictionary).

def RomanNumberConverter(number):
	makeList = list(str(number));
	result = [];
	for num in makeList:
		
		# get value(a dictionary) from NumLength dictionary
		# get roman number from this value(a dictionary)
		firstNumber = NumLength[len(makeList)][num];

		# remove first digit from list
		makeList = makeList[1:];
		result.append(firstNumber);
	return ''.join(result);

while True:
	userInput = input("Input Number: ");
	if not userInput:
		break;
	print("Roman Number: %s\n" %RomanNumberConverter(userInput));

The following is an output result from our simple program. Just press Enter to terminate the program.

Input Number: 2935
Roman Number: MMCMXXXV 
Input Number: 1990 
Roman Number: MCMXC 
Input Number: 365 
Roman Number: CCCLXV 
Input Number:

Here, is RomanNumber.py

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.