Reverse Roman Numerals Reverse Roman Numerals
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In this CheckiO mission Roman Numerals you have to convert a decimal number into its representation as a Roman number.
Here you have to do the same but the other way around.

You are given a Roman number as a string and your job is to convert this number into its decimal representation.

A valid Roman number, in the context of this mission, will only contain Roman numerals as per the below table and follow the rules of the subtractive notation.
Check out this Wikipedia article for more details on how to form Roman numerals.

Numeral Value
I 1 (unus)
V 5 (quinque)
X 10 (decem)
L 50 (quinquaginta)
C 100 (centum)
D 500 (quingenti)
M 1,000 (mille)

Input: A Roman number as a string.

Output: The decimal representation of the Roman number as an int.


reverse_roman('VI') == 6
reverse_roman('LXXVI') == 76
reverse_roman('CDXCIX') == 499
reverse_roman('MMMDCCCLXXXVIII') == 3888

len(roman_string) > 0
all(char in "MDCLXVI" for char in roman_string) == True
0 < reverse_roman(roman_string) < 4000

CheckiO Extensions

CheckiO Extensions allow you to use local files to solve missions. More info in a blog post.

In order to install CheckiO client you'll need installed Python (version at least 3.8)

Install CheckiO Client first:

pip3 install checkio_client

Configure your tool

checkio --domain=py config --key=

Sync solutions into your local folder

checkio sync

(in beta testing) Launch local server so your browser can use it and sync solution between local file end extension on the fly. (doesn't work for safari)

checkio serv -d

Alternatevly, you can install Chrome extension or FF addon

checkio install-plugin
checkio install-plugin --ff
checkio install-plugin --chromium

Read more here about other functionality that the checkio client provides. Feel free to submit an issue in case of any difficulties.

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