First uncategorized solution for Roman Numerals by artemrudenko - python coding challenges

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First solution in Uncategorized category for Roman Numerals by artemrudenko

# migrated from python 2.7
def checkio(number):
    'return roman numeral using the specified integer value from range 1...3999'
    roman = ''
    romanmappings = {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" }                     
    for intVal in sorted(list(romanmappings.keys()), reverse=True):
        while number >= intVal:
            roman += romanmappings[intVal]
            number -= intVal
    return roman
    

if __name__ == '__main__':
    assert checkio(6) == 'VI', 'First'
    assert checkio(76) == 'LXXVI', 'Second'
    print('All ok')

April 6, 2011

Comments:

funningboy on Feb. 5, 2013, 2:06 p.m.
<pre class='brush: python'> 400: "CD", 500: "D", 900: "CM", 1000: "M" } </pre> nice

tcghost on June 23, 2013, 10:35 p.m.
no need for a dictionary in this case since you're just iterating through it, you can just use a list of tuples: romanmappings = [(1000: "M"), ..., (1, "I")] and do: for key, val in romanmappings: but nice and concise solution

lazygoose on Aug. 7, 2013, 9:16 p.m.
Given your answer, mine is ugly enough to be covered with dirt.

Vachenzo on Aug. 8, 2013, 2:49 p.m.
You can always take lessons from the success of others and improve yourself! lazygoose, you have homework: Come up with another solution, make it clean and elegant, then report back!

bafuda on Aug. 9, 2013, 6:42 p.m.
Took me awhile to realize you could treat the 4s and 9s as numerals! Definitely the way to do it.

kubic7 on Aug. 21, 2013, 9:31 p.m.
Pretty smart and elegant!

mr147258369 on Sept. 3, 2013, 12:19 a.m.
Nice

Jaward on Sept. 4, 2013, 1:01 p.m.
Smart.

alexche_8 on Sept. 5, 2013, 3:10 p.m.
Cool

Listjj on Sept. 6, 2013, 4:11 a.m.
The book,"dive into python", have the answer!

fearednerd on Sept. 10, 2013, 7:54 p.m.
Great use of dict... I should have used a dict =(

Reloader on Sept. 16, 2013, 9:47 a.m.
Me too... thought about it at the start of solving problem but I'm still not having enough experience to connect expressions like this one, seen in line 7. Great job!

nptwz on Sept. 20, 2013, 2:39 p.m.
Fantastic

Tanmaya_Meher on Sept. 28, 2013, 4:53 p.m.
The best trick !!!

volodymyrko on Sept. 30, 2013, 2:24 p.m.
you can also do without the while loop: <pre class='brush: python'>for intVal in sorted(romanmappings.keys(), reverse=True): roman += romanmappings[intVal] * (number // intVal) number %= intVal </pre>

GHfan on Oct. 19, 2013, 2:59 p.m.
i always think a way could tear the number apart ,this is it.

RcThrawn on Oct. 28, 2013, 6:59 p.m.
<pre class='brush: python'> roman = '' </pre> The dictionary idea, corresponding with subtracting the intVal was very clever. I'm going to have to remember this in the future for different projects. Thanks!

leo.li on Nov. 2, 2013, 10 a.m.
nice

SapienCS on Nov. 4, 2013, 2:22 p.m.
I did it exactly the same way and now when I've seen this top solution I feel kinda proud of myself :)

floord on Nov. 4, 2013, 3:06 p.m.
Haha you should feel proud! :)

Pteryx on Nov. 9, 2013, 12:53 a.m.
Good idea, elegant realization.

Antonf26 on Nov. 12, 2013, 3:18 p.m.
<pre class='brush: python'> while number >= intVal: </pre> awesome, feel silly not having thought of it!

vstorm on Nov. 15, 2013, 8:26 a.m.
good solution

Candy_GHL on Nov. 22, 2013, 12:39 p.m.
Elegant!!!

nicog123 on Nov. 29, 2013, 10:26 a.m.
Great solution!

julioctadeu on Nov. 29, 2013, 7:19 p.m.
<pre class='brush: python'> 400: "CD", 500: "D", 900: "CM", 1000: "M" } </pre> Nice work!

ysenko on Dec. 5, 2013, 11:34 a.m.
<pre class='brush: python'> romanmappings = {1: "I", 4: "IV", 5: "V", 9: "IX", 10: "X", </pre> You can get rid of <pre class='brush: python'>... sorted(romanmappings.keys(), reverse=True): </pre> by using tuple (or list) instead of this dict: <pre class='brush: python'>romanmappings = ( (1000, 'M'), (900, 'CM'), ... ) </pre> Sorry the top rated solution should be more elegant.

marshall.zheng on Dec. 9, 2013, 1:11 p.m.
Nice!

forrest1988 on Dec. 11, 2013, 9:09 a.m.
quite nice

snipsi on Dec. 11, 2013, 10:10 a.m.
<pre class='brush: python'> romanmappings = {1: "I", 4: "IV", 5: "V", 9: "IX", 10: "X", </pre> Great idea!!

wccrawford on Dec. 12, 2013, 6:50 p.m.
Mapping out the combinations was the right way to go. Somehow, I can never resist doing it logically instead, but the code is always harder to read and less efficient my way.

justMaD on Dec. 13, 2013, 5:48 p.m.
Somehow mapping always makes it "easier", but I tend to not go that route and try to express the underlying rules as methods :D

datruth29 on Dec. 16, 2013, 12:48 a.m.
Love it. Simple and efficient. One thing to not, you don't have to call the keys function on the dictionary; when you sort a dictionary, it always returns the keys in sorted order.

rhcoder on Dec. 16, 2013, 3:16 a.m.
Awesome! Mine is a 99 line of Code. It proves that how dumb I am in programming.. Really..After coming to Checkio I am learning a lot of Python by seeing this solutions..

username724 on Dec. 18, 2013, 2:46 a.m.
Pretty good. Could be simplified a bit, like make the dictionary backwards to start with. And instead of using a dictionary, use a list of tuples. That's what I did ;-)

tuxninja on Dec. 19, 2013, 5:49 a.m.
Well done sir! Better than mine...but I was so close ! :-)

Stazis on Dec. 21, 2013, 9:08 a.m.
Original!

Metropolis51 on Jan. 9, 2014, 10:33 a.m.
We had almost the same idea :)

zulqarnain on Jan. 10, 2014, 3:17 a.m.
i had this idea, but i'm a beginner in python.. i don't know how to declare a dict.. at least now i know how to declare a dict..

atrioom on Jan. 10, 2014, 10:03 a.m.
I like the simplicity, but you are kind of hardcoding every exception. Hmm...

ignalion on Jan. 15, 2014, 7:22 p.m.
It's nice but I was hoping for more elegant solution as a top rated one.

vladimir on Jan. 21, 2014, 9:15 p.m.
romanmappings change to tuple and remowe while

ihatepants on Jan. 23, 2014, 9:12 p.m.
Excellent solution. This is how I had thought about doing it, but could not come up with a way to iterate through a dictionary. Thanks for the lesson!

Stavitsky on Jan. 27, 2014, 6:39 p.m.
Wow. No words.

tyomniy on Jan. 29, 2014, 11:52 a.m.
real good!

dunipan on Feb. 21, 2014, 3:02 a.m.
Great solution. So the while loop understands to take whatever the next highest intVal in can find in romanmappings? so for 622 as an example it would find D for 500 first then C for 100 etc..

serhiideliiev on Nov. 10, 2014, 11:53 p.m.
I also used a dictionary, but have a less smart loop.

rajsharmabannu on May 29, 2015, 10:24 a.m.
same as mine! nice one! :)

Tidjei on Dec. 14, 2015, 4:01 p.m.
intask help ~ is the same )

Adamzma on Dec. 31, 2015, 2:56 p.m.
Absolutely best one :)

VangaroooYamada on Nov. 29, 2020, 9:09 a.m.
nice

paul105 on May 11, 2021, 1:01 p.m.
nice solution, clean and simple yet tricky to make dict with all 4's and 9's

kikurage1001 on Aug. 18, 2021, 10:27 a.m.
My code was very long. So your code is informative for me. It is easy for me to understand.

mangeurdecowan on Aug. 26, 2021, 11:38 p.m.
123456789012345678901234567890 good job

kikurage1001 on Aug. 31, 2021, 12:28 a.m.
Very simple and readable codes. If you use division, your code will run faster.

tssrkt777 on Oct. 3, 2021, 9:39 a.m.
It's amazing! So minimalistic, I admire it.

kaktycuha on Oct. 29, 2021, 6:37 p.m.
Hello, I studied your solution, it is quite interesting. My solution is longer.

roman.xlsm on Nov. 15, 2021, 4:38 p.m.
Great solution using dicts! I made something smiilar, but it has for instead of while, like you did. Congrats! Ots very clear :D

wangjianyu557 on Dec. 17, 2021, 3 p.m.
nice method

barbarian67 on May 6, 2022, 6:15 p.m.
I like this solution, is the old fashion way of programming. Although, perhaps, a list of tuples would be more manageable and easy to hand it with, conceptually romanmappings is clearly a dictionary and for this things are de conversions functions.

Vaarwel on June 26, 2022, 11:55 a.m.
dictionaries is awesome. I especially liked the extended approach when you include not only single letters but also combinations of those, looks very clear and short of code

PosTerrieur on Sept. 29, 2022, 12:16 p.m.
Use dictionary, it's an incredible solution. It's amazing !! Great job

DDela on Oct. 20, 2022, 7:10 a.m.
niceu

DDela on Oct. 27, 2022, 7:13 a.m.
very good idea

DDela on Nov. 23, 2022, 10:04 a.m.
Code-review should be at least 30 symbols long and it should be a commment for the solution (not a reply to another comment).

burgerlolo314 on Dec. 10, 2022, 7:44 p.m.
Nice, it appears very clear to me and it is way better than mine. Thank's for the code, it's helpful to improve myself !

H0r4c3 on Dec. 25, 2022, 8:30 p.m.
Nice!

DDela on Jan. 4, 2023, 11:25 a.m.
Code-review should be at least 30 symbols long and it should be a commment for the solution (not a reply to another comment).

DDela on Feb. 1, 2023, 8:35 a.m.
Code-review should be at least 30 symbols long and it should be a commment for the solution (not a reply to another comment).

DDela on Feb. 15, 2023, 11:45 a.m.
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa

Ivan_Malashenko on Feb. 16, 2023, 7:23 p.m.
for drying code you can use "sorted" without "list" sorted(list(romanmappings.keys()), reverse=True) == sorted(romanmappings.keys(), reverse=True)

eegoldstraw on March 11, 2023, 5:01 p.m.
Nice and short. I like this. A few comments would be even better:)

m.kurapov on July 13, 2023, 8:08 p.m.
You can avoid sorting if you will use list of tulpes.

DDela on Oct. 6, 2023, 8:29 a.m.
nice

Pactp on Oct. 26, 2023, 7:42 a.m.
Nice solution. Helps to aviod additional checking on 4,9 and so on )

mangeurdecowan on June 18, 2024, 9:07 a.m.
This is a nice solution. As others have stated, the use of pre-set values for keys%10**x == 4 or 9 is clever.

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