Hacker News Reader

Now I know what that particular symbol means! Except that it looks kind of like a down arrow, and that link suggests it’s Grade Down.

Would writing argsort(name_of_array, reverse=True) really be so much worse? Or argsort[reverse] (made up syntax) if you want a point-free function form?

View on HN

It's not sort. In Kap, sort down is ∨. The grade functions returns a sorted index. Basically ⍒ 3 1 2 1 1 returns 0 2 1 3 4. So yes, it performs a sort, but it returns an index that can be used to later look up the respective elements.

You can read more about it here if you're interested: https://www.aplwiki.com/wiki/Grade

And here's a silly example where a random array is created, then an array lookup is performed on the sorted indexes:

https://kapdemo.dhsdevelopments.com/clientweb2/#a%20%E2%86%9...

That’s why I said argsort :)

https://numpy.org/doc/stable/reference/generated/numpy.argso...

I assume this name derives from argmin and argmax, which go back at least to MATLAB. But MATLAB has sort returning indices too.

You are correct, it is "Grade Down".

Some people prefer terseness, think of this as "advanced next-level Perl one-liners" if that helps ...

Reply on news.ycombinator.com