Second clear solution for Xs and Os Referee by gyahun_dash - python coding challenges

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Second solution in Clear category for Xs and Os Referee by gyahun_dash

def checkio(result):
    rows = result
    cols = map(''.join, zip(*rows))
    diags = map(''.join, zip(*[(r[i], r[2 - i]) for i, r in enumerate(rows)]))
    lines = rows + list(cols) + list(diags)

    return 'X' if ('XXX' in lines) else 'O' if ('OOO' in lines) else 'D'

April 12, 2014

Comments:

horizon0514 on June 2, 2014, 1:40 p.m.
wonderful

gyahun_dash on June 3, 2014, 4:01 p.m.
Thank you.

timur.hamzin on June 12, 2014, 3:31 p.m.
It's beautiful! A little explanation would be helpful for beginners like me, though, since everything in this solution was new for me - starting with asterisk arguments and ending with enumerate function. Just one question: aren't cols and diags lists already?

gyahun_dash on June 12, 2014, 6:32 p.m.
Thank you. I'm happy if you've gotten something new. <blockquote> Just one question: aren't cols and diags lists already? </blockquote> They are lists in Python 2, but not in Python 3. map returns a iterator here, so they need to be changed to list.

yang.wang04 on July 10, 2016, 9:54 a.m.
Thanks. Got the same question before. It is clear to me now.

tony.hersey on July 3, 2014, 9:07 p.m.
whoa. I'm new to this and you just blew my mind. My solution is a turd salad in comparison.

gyahun_dash on July 6, 2014, 11:50 a.m.
Thank you. I think yours is not bad because it is described clearly. If you shorten your code, <a href="http://www.checkio.org/mission/x-o-referee/publications/DanielDou/python-27/first/">DanielDou's</a> is helpful to you. Its approach is close to yours.

bit.man on July 23, 2014, 4:12 a.m.
Your code is awesome. What does the * do in the zip function args? I have seen it used for variable length arguments but not sure how it works here.

gyahun_dash on July 23, 2014, 3:27 p.m.
<blockquote> What does the * do in the zip function args? </blockquote> It is used for <a href="https://docs.python.org/3.4/tutorial/controlflow.html#unpacking-argument-lists">unpacking</a>. For example, zip(*rows) in my code is equivalent to: <pre class='brush: python'>zip(rows[0], rows[1], rows[2]) # (rows[0][0], rows[1][0], rows[2][0]), (rows[0][1], rows[1][1], rows[2][1]), ... </pre> Thank you.

strangers on Aug. 10, 2014, 11:07 a.m.
Very interesting solution

gyahun_dash on Aug. 10, 2014, 4:44 p.m.
Thank you.

taras-sereda on Aug. 14, 2014, 2:09 p.m.
Brilliant! Reading such code helps me uncover unseen features of Python and learn how they could be applied in practice.

gyahun_dash on Aug. 14, 2014, 4:52 p.m.
Thank you. Also, I've learnt many things in CheckiO. Let's have fun!

mostro on Aug. 17, 2014, 7:30 p.m.
your code is beautiful :D

gyahun_dash on Aug. 18, 2014, 11:14 a.m.
Thank you!

peasant on Aug. 30, 2014, 7:48 a.m.
Clear and pythonic.

gyahun_dash on Aug. 30, 2014, 9:16 a.m.
Pythonic! Thank you!

uogashi on Sept. 5, 2014, 12:49 a.m.
It's a silly thing, but is it ok for you not to declare the 'rows' var and change all the 'rows' into 'result' directly? It's only a line, but it's a doubt I have. Thanks!

gyahun_dash on Sept. 8, 2014, 8:09 p.m.
As you say, it's an unnecessary declaration. I just want to assign lines like line 5 rather than: <pre class='brush: python'>lines = result + list(cols) + list(diags) </pre> Thank you.

uogashi on Sept. 9, 2014, 12:51 a.m.
Thanks! I just wanted to be sure. Pretty amazing solution, by the way.

dsnyder0cnn on Sept. 19, 2014, 11:35 p.m.
I felt like it should be possible to use zip for this, but I gave up on working out the diagonals. It's not obvious to me why you need the list() calls on line #5. Couldn't you just say that "lines = rows + cols + diags"?

gyahun_dash on Sept. 20, 2014, 10:48 a.m.
<blockquote> Couldn't you just say that "lines = rows + cols + diags"? </blockquote> It is possible in py2, but not in py3. Because map returns an iterator.

picklesforfingers on Sept. 27, 2014, 6:25 a.m.
Wow. This is so much shorter than mine. I went off the walls.... Yours makes so much sense though.

gyahun_dash on Sept. 30, 2014, 2:56 p.m.
Thank you! With built-in functions, you can make your codes shorter.

reviewboy on Oct. 1, 2014, 3:15 a.m.
Terrific solution! I aimed for the same logic, but plowed through it the hard way; your code is so much more elegant. I love the use of map()!

gyahun_dash on Oct. 1, 2014, 10:38 a.m.
Thank you! map and zip often help me. I love them.

mikewr80 on Oct. 21, 2014, 7:16 p.m.
Nice work buddy!

gyahun_dash on Oct. 24, 2014, 3:28 p.m.
Thank you!

icbruce on Nov. 7, 2014, 10:22 a.m.
This is awesome!!!!!! A cool method with map and zip.

gyahun_dash on Nov. 7, 2014, 3:55 p.m.
Thank you!

mydaemon on Nov. 10, 2014, 9:38 a.m.
Wonderful, you followed my own solution, but mine is hardcoded, while yours use internal features of the language. Yours would scale much better for any size, with little changes. You deserve to be where you are in the list :)

gyahun_dash on Nov. 13, 2014, 3:40 p.m.
Thank you!

tadashi on Nov. 15, 2014, 12:08 p.m.
so smart!

gyahun_dash on Nov. 23, 2014, 7:23 a.m.
Thank you!

JivanRoquet on Dec. 6, 2014, 3:34 p.m.
Very smart - congrats

gyahun_dash on Dec. 11, 2014, 1:17 p.m.
Thank you!

LLCheckio on Dec. 9, 2014, 7:49 p.m.
I'm sorry if my question is stupid, but what about a situation where we find both 'xxx' and 'ooo' at the same time? Will we get 'X' or 'D'?

gyahun_dash on Dec. 11, 2014, 1:17 p.m.
In this case, this solution returns 'X' or 'O'. I believe that it never occurs in real situation.

l2032 on Jan. 10, 2015, 2:50 p.m.
nevertheless, the description calls for returning 'D' in this scenario. I do LOVE your approach, much much cleaner than my overly convoluted approach.

caynan on March 14, 2015, 8:50 a.m.
amazing, what you've done in `diags` the use of zip was simple and really smart of you.

mauricioabreu on March 28, 2015, 2:20 p.m.
Good solution. My solution uses map and filter. :-) Good job, thank you!

Peter.White on March 31, 2015, 10:06 p.m.
Nice. But the last line I don't like all that much. There is a variable in there, the player. The two ifs are basically the same only different players.

psystyle on April 8, 2015, 7:54 a.m.
Your solution taught me a lot of things!

dsethlewis on July 30, 2015, 7:20 p.m.
I know, who ever heard of map, zip, join, enumerate, list, *? I'm still trying to figure out how to put for loops in a single line.

rajsharmabannu on May 25, 2015, 10:14 a.m.
I am on level 7 right now and still I use the conventional (sometimes,hard-coding) techniques to solve the problem and I know that i'm not using Python the way it is meant to be. IDK when i'll be able to code the Pythonic way. Is there a way to remember things in Python? If yes, then how? :/ But anyway, this code of yours has a brilliant approach! :D

Butch on June 23, 2015, 6:49 p.m.
Like it!

regan.ryan.nz on Aug. 29, 2015, 2:57 a.m.
Diags is too hard to understand O.o

ppcv on Sept. 5, 2015, 2:57 p.m.
clear

p42es on Sept. 22, 2015, 7:10 p.m.
(cols is 'beautiful') and (diags is 'crappy') != Clear_leader My decision clearer though not so sweet.

tarjeii on Oct. 24, 2015, 2:54 p.m.
very good

sanya0971 on Jan. 20, 2016, 3:22 p.m.
Perfect

sshishov on Jan. 22, 2016, 8:22 a.m.
The best!

bbbass123 on Jan. 29, 2016, 5:07 p.m.
Its so good you may as well rename the in parameter to rows and save a line! Nice.

AsEsm on Feb. 2, 2016, 8:57 a.m.
u OWNG!!!!! before i used some big func and loops for take columns.

laetrid on April 13, 2016, 3:50 p.m.
Great solution!

Angela_Wang on Aug. 30, 2016, 10:13 p.m.
Smart and clear!

Thenbacker on Sept. 29, 2016, 6:25 p.m.
Great, nice compact readable code!

jonathan.crescini on Aug. 28, 2017, 4:26 p.m.
The diags line is brilliant!! Well done

art8008 on Sept. 2, 2017, 10:01 a.m.
It has too much magic, i suppose, but it's nice the same time:) Thank's!

MrMike on Sept. 23, 2017, 6:28 p.m.
Thanks for this solution, as a newbie nice to learn what is possible with python!

pumacens_ceb54daf41d74653bc014 on Oct. 13, 2017, 10:32 p.m.
que gonorrea parce :,v

ajmal.nazir on Nov. 13, 2017, 8:22 p.m.
lol.... incredible... I think I wrote the longest code possible to get the solution.... this is amazing...

iz0823 on Dec. 11, 2017, 10 p.m.
The beauty of simplicity.

ivantps on May 20, 2018, 5:54 p.m.
Still struggling on "diags" line.... Nice art pieces!!

mayuyu4c on May 30, 2018, 4:09 a.m.
spent 10 mins to understand ur solution, so impressive

matrixwzd on July 15, 2018, 8:02 a.m.
WOW! Amazing!!!

xero786 on Aug. 11, 2018, 8:48 p.m.
Genius. Respect bro !!!

tang_xiaoting on Sept. 3, 2018, 1:38 a.m.
awesome solution.

ljpGBL on Sept. 26, 2018, 8:31 a.m.
This is pythonic!

pumacens_64305eb2e37c43308c6c7 on Oct. 23, 2018, 3:44 a.m.
Que gonorrea :,v

strongyin on Nov. 18, 2018, 2:04 p.m.
amazing！

Onlyme328 on Nov. 26, 2018, 8:19 a.m.
AMAZING

Fr3nzy on Dec. 2, 2018, 8:37 p.m.
Thank you, I have learned a lot in a few lines ! I did my best to try and explain this, hope this is clear and correct enough. <pre class='brush: python'>rows = result # Easier with an example : # rows = [ 'XOX', 'XXO', 'XO.' ] # * (unpacking) removes the [] : # A = *rows = 'XOX','XXO','XO.' # zip does tuples with all first items, then all second items, etc : B = zip( *rows ) # = [ ('X','X','X'),('O','X','O'),('X','O','.') ] # ''.join( tuple ) join each element of the tuple with separator ''. # map applies the join function to each tuple in the list B : cols = map( ''.join, B ) # = [ 'XXX', 'OXO', 'XO.' ] # enumerate( rows ) return in tuples each element r of rows with a numeric counter i added to it : C = enumerate( rows ) # = [(0, 'X.O'), (1, 'XX.'), (2, 'XOO')] # r[ i ] takes 1st element of 1st line of rows, then 2nd element of 2nd line, then 3rd element of 3rd line -> 1st diagonal. # r[ 2 - i ] takes 3rd element of 1st line of rows, then 2nd element of 2nd line, then 1st element of 3rd line -> 2nd diagonal : D = [ ( r[i], r[2 - i] ) for i, r in C ] # = ('X', 'O') ('X', 'X') ('O', 'X') # Then unpacks with *, zip to put all the r[i] together (first diag) and all the r[2-i] together (second diag), then map with join, same as before : diags = map(''.join, zip(* D ) ) # Concatenates all the possible lines (3 rows + 3 columns + 2 diagonals) : lines = rows + list(cols) + list(diags) # Final check : return 'X' if ('XXX' in lines) else 'O' if ('OOO' in lines) else 'D' </pre>

jiizzyy on Feb. 8, 2020, 8:56 p.m.
You are my hero today!

MikeP on Oct. 18, 2022, 4:49 p.m.
could you please explain me why C is like it is?)

Anna_Khv on Feb. 5, 2019, 1:25 p.m.
wow, awesome code

z.thami on June 4, 2019, 2:45 p.m.
Looks like a verry nice solution, even though i dont fully understand it. :) -Just a beginner... ehmm But WAY shorter than my hardcoded version. I obviously need to read up on map() and zip(). GJ!

oerba on June 17, 2019, 7:28 a.m.
Great

Zielm4n on June 22, 2019, 1:54 p.m.
Awesome solution! I learnt a lot about map() and zip() funcs because of it!

umetarou on Nov. 10, 2019, 12:20 p.m.
good

atikin88 on Feb. 18, 2020, 1:30 p.m.
Nice!

igharok on Feb. 19, 2020, 1:16 p.m.
Simply the best

katharina.noreia on March 4, 2020, 10:11 p.m.
Very elegant

piter239 on April 28, 2020, 8:41 a.m.
I learned something new from your solution, it is pretty and self-documented. There is still something I would do different, and that is handling of edge cases in line 7. For example, your solution returns 'X' for [“OOO","XXX","OX.”] I think it has to be 'D' for "Draw", because we cannot decide who was the first to score. My fix for it would be <pre class='brush: python'>score = {sym: lines.count(sym * 3) for sym in 'XO'} return "DXO"[bool(score['X']) - bool(score['O'])] </pre> Which correctly handles situations where both sides have scored. My solution using your nice self-documented style <a href="https://py.checkio.org/mission/x-o-referee/publications/piter239/python-3/second-improved-readability-while-maintaining-correct-handling-of-special-cases/#comment-86423">is here</a>.

ainoneko on June 18, 2021, 3:48 a.m.
IMHO, the [“OOO","XXX","OX."] position is not possible in a real game, so the result is not really meaningful.

koborC on Aug. 13, 2021, 6:48 p.m.
great answer! also, <pre class='brush: python'>r[2 - i] # in line 4 </pre> can be written as: <pre class='brush: python'>r[~i] </pre>

Guest_5a80b5eb on March 4, 2022, 3:44 a.m.
This might be a good time to use chain instead of expanding the maps to lists. <pre class='brush: python'>lines = itertools.chain(rows, cols, diags) </pre>

9214491 on Nov. 24, 2022, 7:44 a.m.
Not very easy for a beginner to understand

burgerlolo314 on Dec. 31, 2022, 10:02 a.m.
wow this solution is incredible for a beginner like me, congrats !

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