7 kyu
Return substring instance count
2,005 of 8,204jhoffner
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Strings
Fundamentals
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Haskell translation
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you did not use markdown formatting, so your code is hard to read. from what i see, you seem to be only considering the case
len(search_text) == 2, but your solution has to work for any length.You should ask a
questionto ask for help;issuesare provable bugs within the kata. this guide can help you troubleshooting your solutionThis comment has been hidden.
matchAll()does not return an array, it returns an iterator. An iterator has nolengthproperty, and JavaScript defaults toundefinedwhen you access a non-existent property on an object.This comment has been hidden.
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Python update (new testing framework)
Approved
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Falsifiable (after 14 tests): "zzaaaza" "aaaz" 2 expected 2 but got 1
I don't get this kata. How can you find "aaaz" from "zzaaaza" twice?
C translation (without overlap or empty substrings)
Approved
this should be level 8 , no need to be 7
Not all languages are so trivial, so, 7 kyu is ok. Note kata ranking can't be changed either.
I see.
The description doesn't say if we should count overlapping substrings. This should be stated and all versions should be coherent with it; currently there are no overlaps or they should not be counted in Python, but it's the contrary in Haskell and JS.
I don't see any overlapping test in JS, are you sure about that?
My bad, not in JS (but in Haskell).
Haskell fixed ( ~60 solutions invalidated :] ); description already mentioned overlap not allowed ( probably did not always do so ).
Closing.
In Haskell the substring may be empty, and we are supposed to return the full string length in that case. It doesn't make sense.
perhaps
full string length + 1would make more sense :pafter all
O_o
Well, in Python too there may be empty strings... To me the logical answer to this would be infinity...
Substring is now never empty. Closing.
(
length + 1would make sense to me, but try explaining that to the target audience of the kata .. )This comment has been hidden.
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BROKEN KATA
Broken how?
Why does an empty string substring match length of the string times? Should this behavior be explicitly called out in the instructions?
The tests need a complete rewrite to include random tests.
Issue not useful without mention of affected languages. Closing.
When reopening, please specify language(s).
Issue on C# Can't submit my solution : fixture.cs(23,71): error CS0120: An object reference is required to access non-static member `Kata.SubstringCount(string, string)'
Fixed sample code.
Kata.SubstringCountneeds to bestaticThank you for helping, it works !
In the testcases the function is called
solutionbut in the function declaration it'ssolve.Fixed (it's Haskell version btw).
Ah yes, sorry -- I should have realised that the issue wouldn't automatically be tagged with the language.
Haskell translation
Please review and approve.
Old and too simple... Nothing to gain for new Python players... Nothing to gain to translate it in Python except points on the leaderboard...
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While I appreciate reading new katas, even simple ones, this kata brings nothing to a beginner more than reading documentation: literally nothing more than a built-in function. From more advanced player's view, it is extremely boring to see nothing new but such tremendously simple katas. Boringness won't help CW keeping both new and old players entertained.
Moreover you translated a three year old inactive kata that even a profilic kata creator stated as unqualified. I simply didn't grasp the point of your decision at the moment and I still don't grasp it now. You explained that you translated this kata to see when people start complaining: I don't usually have much to complain about your katas, but if that is your only purpose, I find it quite mischievous - I think CW is a place for sharing and entertainment, so please refrain yourself from bringing such madness here and keep the good work!
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Then just two questions:
Ad 1st question: As I know, it's possible. But after I'd seen kazk's struggles with adding new stuff (see here) I decided rather step back as I have other things to do :) In my understading, the 500-solvers rule isn't solely a technical issue. jhoffner could tell more about the motivation behind this rule.
Ad 2nd question: Maybe, I've never tried to check what 3rd party libraries are available. However, use vanilla JS without third party stuff (immutable.js, JQuery etc.) to feel the "authentic pain"* :D I remember my feelings (or frustration :)) when I first tried js.checkio.org and I had to write 10 lines using
fors andifs instead of a cute, little Python one-liner :)Regards,
suic
* To be honest: I don't like JavaScript. On the other hand, I don't think that JS is an a priori bad language :)
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This should be a very old Kata, with the CW standard to measure it now, it is not qualified.
It does not have example testcases,and random testcases, and the difficulty is not suitable as a 6kyu.
It's 7 Kyu
Shouldn't there be a test case where some strings are uppercase? The more popular solutions would fail that case, wouldn't they?
I think this is a bit easy for a 6 Kyu.
It's 7 Kyu
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Imagine having an input string like "ababa" - you want to count the b's.
Split on b will chop up the string into three parts - similar to what you naturally do ig the b's were replaced with a comma. In this case it will count one item too much as you are really just interrested in counting the commas.
Scan on the other hand will pick out only the b's ignoring the rest giving you a count of two b's.
thank you very much for your reply. like 'abab',i want to count the b's. when the last letter is b after I use the 'split' method,the result will be two. 'abab'.split('b') = ["a","a"] that's where i am wrong .
Wow. The kata is that popular and old, but have some problems.
#First Tests check too few cases. My solution had serious bug, but have passed the tests, because it's not too unlikely to pass only 4 tests when a solution does almost what it must.
#Second The description doesn't state, what kind of text a solution must accept as input. Is it alpha-numeric only? Or is it a regular text - "Yo, man", "whatcha gonna do", etc.?
It looks like most of people who solved the kata have considered code examples in the description as a hint like "no special characters here!". So the best solution is to state "Input string consists of a-z, A-Z, _ and space", for example.
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Read carefully about return values of String.match. https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/match
Thanks Firnis. In most of the kata I've done thus far, the Attempt method returns some type of error message when it does not work, so I was looking for that. Didn't think about returning null vs. 0.
How about adding empty string to possible searchText values? Test.expect(solution('aaaa','') == 0);
Also Test.expect(solution('aaabb', '.') == 0, "solution should not assume search text is safe to use as a regular expression")
Excellent suggestion. Adding that will break probably every single solution given. I think I might create a new, harder version of this kata that takes the following signature:
Unless of course someone else is up for creating the new kata and earning the honor for doing it :)
First post? http://www.codewars.com/dojo/katas/52190daefe9c702a460003dd
You rock!
Test.expect(solution('aaabb', 'aa') == 2, "solution should return correctly count overlapping search results ")
I agree with this. I built my solution with this in mind.