Awesome. Thanks @Adám

Is there a way to do "max by" in J without resorting to Agenda. Ie, Try it online!

Sort also works, but is inefficient: ] {.@\: {:"1

@Jonah Just so I understand right, you want the row that has the first max value in the second column?

⍞←(⊢⌷⍨∘(⊢⍳⌈⌿)⊢/) 4 2 ⍴1 3 1 8 2 4 9 5

@DyalogAPL Hey, were are you?

@Jonah Reduction without agenda.

@Bubbler ty, that’s what i was looking for

@nathanrogers Did you get enough of an answer from support@?

heh, the length error here fails to point to anything

@dzaima That's odd. It works fine offline for me.

@Adám doesn't for me

@dzaima Right, I just tried in 17.0 where it indeed doesn't. 18.0 works.

I fully understand how painstakingly annoyingly hard can getting that fancy pointing to errors thing to work perfectly can be (I half gave up trying to for my APL :/) though

oh, nice

@dzaima It got a whole lot better in 17.0. Before that it was pointing at the leftmost point that was parsed, even if the error was far away.

yeah. Knowing that there was effort for that is why I asked

@dzaima Ah, right so it must have been a glitch in the caret moving code for 17.0. 16.0 has a normal message but the caret is all the way left since the parser finished before the length error. I'll point the 17.0/17.1 error out, as I suppose we can backport 18.0's fix.