@FawnLocke As you note, the ecosystem of Dyalog is relatively very large, and that is not necessarily bound to change. BQN may or may not develop a big ecosystem.

More importantly, its never clear in the moment that a new design is not simply making a a whole bunch of new mistakes as it seeks to correct all the old mistakes. I think J was supposed to fix all of the mistakes of APL, like having a special character set.

I guess we'll see. I appreciate the response

how to filter?

0 1 0 0 1
1 0 0 1 1
1 0 1 0 1
0 1 0 1 0
0 1 0 1 0

^ and 1 and the other argument

outputs

1 0 0 1 1
1 0 1 0 1

you should be more specific by what you mean by "filter"

do you have a predicate function and you want to return all elements that pass the predicate?

i want a dfn, taking ⍺ as a bool matrix and ⍵ as a bool value

that filters ⍺ outputting only the rows which start with ⍵

Advent of Code 2021?

I just used traditional array index for part 2

followed by ⌿ filter. all in a while loop with tradfns

both this one and yesterday's part2 discourages array oriented thinking. I didn't even choose APL for yesterday's part2 (and use Lisp instead).

good day

I must say I have a pretty tasty part 2 for today's AoC

I'll publish my solutions so far later today

Did you manage to do it without power or recur?

i didnt even manage to do the part 2

@xpqz No not that tasty

Is that possible? I could see someone fudging a scan but the dependency seems unavoidable

Not sure it’s possible

The thing I like is I have a scrub operator, so I can use ≤_s for one and >_s for the other

Ha. I did the same!

My solution for today's AoC: gist.github.com/klao/b37b9a8f28c8235972ce94e8d6cc9f0e

@xpqz we are also neck-and-neck in rak's leaderboard... suspicious...

@RikedyP Ooh, interesting, I'll try to rewrite my solution to use an operator. Haven't tried to write an operator before…

@klao It's literally just once you spot that you'd have identical code but with the comparitor switched, swap the ≤ for ⍺⍺ and your dfn becomes a dop like magic

@RikedyP Yeah, I passed a "bool" parameter to my scrub on the left and xored the result of the comparison with it. So, I don't have duplicated code, but the operator is way nicer!

github.com/rak1507/Advent-Of-Code-APL/blob/main/2021/…

todays

@RikedyP yea I did the same

Mine: gist.github.com/xpqz/d406eb493fd2a875ae463cce009463af

you haven't added 'fn'

Disgraceful. Try now.

On reflection, probably had been neater with ∇ instead of ⍣.

always happy to see a differential operator in code :)

Spot the mathematician...

@xpqz nice

thanks

neat solution

@PyGamer0 m⌿⍨1=⊣/m

@Adám how does it work?

⊣/m gets the leftmost column of m. 1= gives you a boolean vector, 1 for rows you want to keep, 0 to discard. m⌿⍨ uses that to filter the rows of m

@milia judging by it's usual usage, it's probably a bit more like gradient operator