short and clear clear solution for Roman Numerals by StefanPochmann - python coding challenges

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short and clear solution in Clear category for Roman Numerals by StefanPochmann

def checkio(n):
    result = ''
    for arabic, roman in zip((1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1),
                             'M     CM   D    CD   C    XC  L   XL  X   IX V  IV I'.split()):
        result += n // arabic * roman
        n %= arabic
    return result

April 18, 2015

Comments:

vananabu on Aug. 18, 2015, 2:12 p.m.
There is one question after your solutions: 'why did not I think of that?' it's so simple :) bravo!

tarjeii on Nov. 2, 2015, 7:30 p.m.
Fantastic

not_real on Dec. 9, 2015, 12:54 a.m.
It take me a moment to understand that <pre class='brush: python'>result += n // arabic * roman </pre> means: put in `result` string (`n // arabic`) times the `roman` string

suiluj_julius on Jan. 21, 2016, 4:21 p.m.
Nice but rather difficult to get for me, what is the n %= arabic exactly doing?

ptillemans on Sept. 10, 2016, 3:31 p.m.
it replaces n by the modulo of the value of the current roman number.

grutte_pier on May 25, 2016, 8:43 a.m.
Nice solution indeed!

Mellivoran on Sept. 11, 2016, 11:22 p.m.
Forgive my naivete, but what does zip-split get you that [(1000,'M'), (900,'CM'), (500,'D'), (400,'CD'), (100,'C'), (90,'XC'), (50,'L'), (40,'XL'), (10,'X'), (9,'IX'), (5,'V'), (4,'IV'), (1,'I')] doesn't? I like the vertical organization of having the M below 1000...is that it?

veky on Sept. 26, 2016, 1:09 p.m.
Of course. If you want to transpose that organization, see <a href="https://py.checkio.org/mission/roman-numerals/publications/veky/python-3/enum/share/22e044ab85d2e00f7c2bb4b0c7550f41/">this</a>.

Sim0000 on Sept. 13, 2016, 11:25 a.m.
Really short and clear :-)

Kyiran on Sept. 14, 2016, 7:02 p.m.
At this moment in time I wonder if I am encouraged or discouraged to continue with coding :). But with regards to your performance: Absolutely great

mikeroo on Jan. 8, 2017, 3:28 a.m.
Right? Some people are way above the coding level of I can even conceive of...

minstrel271 on Sept. 15, 2016, 6:38 a.m.
why not use divmod?

cryptograph2013 on Sept. 16, 2016, 9:29 a.m.
Cool, but did not understand "result += n // arabic * roman" line

potens on Sept. 27, 2016, 12:34 p.m.
When you come to this solution, at the first look, you think "where is the end of the code... oh, wait a moment..." and then, you wonder why you have done such complicated things in yours...

Kolrim on Sept. 29, 2016, 4:45 p.m.
I had to google-fu a couple of things (zip() and // specifically) to figure out what was happening, but then it became really clear and awesome. I hope to get my skills up to that level some day. :D

totee19 on Oct. 2, 2016, 9:40 p.m.
Very nice!!!

Sebastian.M on Oct. 7, 2016, 7:57 a.m.
Could the zip be replaced by normal list? Or is it somehow important to have a list of tuples?

DahliaSR on Oct. 14, 2016, 8:09 p.m.
Of course you can use a list instead of tuple. To me using a tuple is better practice as tuples do not support item assignment, which is pretty much what you expect from someting that is actually constant

glenuk on Oct. 17, 2016, 12:27 p.m.
Some comments would be really useful! Very nice solution though.

sohei.akaoni on Oct. 31, 2016, 11:27 a.m.
beautiful

vicp on Nov. 6, 2016, 11:14 p.m.
This is a great solution!

ryan.n.goodner on Nov. 12, 2016, 2:32 p.m.
Good job

skyris on Nov. 28, 2016, 10:33 a.m.
Really nice!

ThibaultGROUEIX on Nov. 30, 2016, 11:02 p.m.
So much simpler than what I did ! Nice and clear

portamundos on Dec. 7, 2016, 12:15 p.m.
Cool, but answer plsease, n %= arabic ?! What is that? How int // str (n // arabic * roman) ?

tkunst on Dec. 20, 2016, 5:05 p.m.
Had to take this through Python tutor to understand how it works. Great solution.

danny.luker_6f2b7a7a6c6340b297 on Jan. 10, 2017, 6:18 p.m.
Sweet! I like the readability (easier to type, too) of your arabic-to-roman map. Neat technique. Very Pythonic I think.

arth_karpenko_ceb680c8f3f44bcf on Jan. 12, 2017, 7:28 a.m.
Very short and cool solution!

shaowenliu on Jan. 16, 2017, 1:32 a.m.
clever!

mrahulagrawal on Feb. 5, 2017, 2:15 p.m.
Great Solution!!

zidansilverlane on Feb. 27, 2017, 5:18 a.m.
hands down most beautiful so far that i have seen and learned from

thelensky on Feb. 28, 2017, 12:20 p.m.
If you append bracket like this "result += (n // arabic) * roman " it be more for understanding

Jason_Zhou on March 12, 2017, 11:24 p.m.
This is so neat and beautiful, great work!

LAyer_8 on March 27, 2017, 1:22 p.m.
This is beautiful

robust1308 on March 30, 2017, 4:45 a.m.
Great!

MrPechi on April 4, 2017, 2:51 p.m.
Beautiful but not clear

Akirallian on April 7, 2017, 10:08 p.m.
Your idea is amazing!

dalluca on May 1, 2017, 2:11 p.m.
Very very nice...

denys.sorokin on May 3, 2017, 10:37 a.m.
Very interesting decision...

afana_daniel on May 14, 2017, 1:20 p.m.
It's all simple mathematics. But since we don't use those operators much in life, it takes a while to understand the code. Neat solution.

vinitrinh on May 18, 2017, 8:16 a.m.
How do you beat that?

keshamin on May 20, 2017, 2:37 p.m.
This is very simple and beautiful, but this code does NOT consider numbers like 950. It returns 'CML', but actually it is 'LM'.

lucrib on May 28, 2017, 10:37 p.m.
This is a really cool and fast solution. Just missing the valiation 0 < data <= 3999.

abehad701 on June 6, 2017, 12:11 a.m.
definitely the simplest. love it!

Sang-Gon__Lee on June 14, 2017, 7:20 a.m.
amazing!!

Andrey_Klymchuk on June 19, 2017, 8:47 p.m.
Thank you. Your solution improved my mind.

tsmile2017 on June 24, 2017, 4:38 p.m.
can't see my code any more...cry..

Apocaliptis on Aug. 14, 2017, 6:42 a.m.
Just brilliant... So easy and short!

quarkov on May 18, 2018, 12:16 p.m.
.split method had been used to avoid an excessive using of the quotation marks or I missed something more important?

soloshowing on June 13, 2018, 7:54 a.m.
When will mine be as good as yours??

lukasz181818 on Sept. 29, 2018, 5:53 p.m.
Very clever, thank you !!!

chchun on Oct. 9, 2018, 1:18 p.m.
excellent!!!

acarpioanon on Oct. 21, 2018, 4:19 p.m.
Awesome. Beatifull mathematical solution. It makes you think about this type of problems.

thinh251 on Nov. 15, 2018, 6:13 a.m.
Unbelievable smart

vlad.bezden on Feb. 14, 2020, 2:58 p.m.
Simplicity is key! Great job!

waxdesf on April 16, 2020, 9:02 a.m.
You just blow my mind. Thank you for improving my understanding of code. I tried to transcode it in JavaScript <a href="https://js.checkio.org/mission/roman-numerals/publications/waxdesf/js-node/credit-stefanpochmann/">here</a>

sveinroed on March 3, 2021, 8:19 p.m.
truly original!

rhodeus208 on July 7, 2021, 9:59 p.m.
Oh I didn't think about preparing 9~~ pairs. It is clever way.

jsg-inet on Aug. 13, 2021, 9:45 a.m.
I like so much your solution, but perhaps it should be published under "Creative" category, only for the "zip" part of the code. :)

kikurage1001 on Aug. 18, 2021, 10:24 a.m.
"zip" is very useful. I was unfamiliar with zip, so your code was very informative.

smalcom on Aug. 25, 2023, 6:22 a.m.
Cool solution. Ten minutes i spent for understanding: it's Python, not C, '//' - it's not a comment start. )

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