Note for the reader: filtering at each step is bad.

Reraised as an issue

Description should be language-agnostic (in function name and examples)

Java:

• actual and expected are swapped

pythonic code

Pretty difficult and complex kata for being ranked a 6th kyu, very well thought.

might be interested:
http://butunclebob.com/ArticleS.UncleBob.TheBowlingGameKata

Because of the sorted bit, a == c means a == b == c, so the equilateral condition can be a == c and the isosceles condition can be a == b or b == c.

TL;DR, it all depends on who you are writing the code for. Personally, I enjoyed it but wouldn't write it.

This feels like an age old argument between concise and readable code. To a complete beginner this would not be very useful or accessible. For me, knowing some JS and a week into learning Python, it is not readable but fun and interesting to dissect and understand, and it helps me to learn. Thank you. And I can easily understand that this becomes quite obvious with time.

Can you explain, please? I wrote the same code..
i'm a beginer and i don't understand why this code is horrible...

The point was to hand-write a recursive function :)

The point of solving the issue was making it as short as possible.
Therefore, using the arrow function and removing the brakets were neccary.

It's clever, but not best practice at all :)

Das wäre in der Tat auch eine Lösung gewesen,
aber ich wollte ja eine möglichst kurze Lösung haben. :P

Davon abgesehen, sollte man die Funktion nicht auf meine Art implementieren, und auch möglichst auch ein reverse mit anschließender for-Schleife ;D