taronish

@Adám Thanks!

What else is new in 18.2 ? ... some more syntax highlighting styles or something along those lines I think, but I don't recall what else.

I would just like to say how much I appreciate this helpful community. You all entertain my questions, and are pretty polite about it when my attempts aren't optimal.

@Adám Thanks for hosting!

I feel like obfuscated is usually most appropriate as a deliberate category ...

@Razetime What qualifies as an enterprise solution? Do we have to use XML or CORBA or something? ;)

@Adám Ah, thank you.

I don't understand the runtime difference between the version that has (+/65≤⍵) vs +/(65≤⍵) ...

Typical robot ...

@Adám I forgot about that ...

The only way to win is ... not to play?

Here's mine: {0=≢⍵:100⋄100×+/(≥∘65÷≢)⍵}

@FawnLocke Ahhh ... that helps a lot. Thank you.

(⊂0 2 3)⌷'ABCDEF'

I'm talking about expressions such as:

Why do we often need an additional level of enclosing of the arguments of ⌷ when using it to index things? I usually mess it up and then just throw in an enclose and it works, but that's not a satisfying approach so I'd like to understand it better.

So is 15 the max (allowed) rank?

Interesting ...

@Adám What sort of test case?

But you're right that if I had just used IO 1, I wouldn't have had to monkey with the output of iota.

@Adám I just write my solutions using IO == 0 typically, and so when I paste them I often add the explicit specification of IO like that ...

Ok, that's a relief, because my solutions are collapsing under their own uglyness as I try to make them pass the test.

(Using , inside the function passed to key means it filled empty spots with 0 ... which is why I used @ ...)

{⎕IO←0⋄' '@{⍵=0}{⍺,((≢⍵)⍴'*')}⌸,⊃∘.+/1+⍳¨⍵} passes basic tests.

(that's what I had arrived at before trying my hand at ⍕)

That gets a similar error, though ... so it still isn't correct.

What is the intended way (maybe just a way I've written the left parameter of key incorrectly?) to get exactly the output that is desired?

But that differs by minor spacing and by the mixed array vs non-mixed array.

{⎕IO←0⋄⍕{⍺ ((≢⍵)⍴'*')}⌸,⊃∘.+/1+⍳¨⍵}

My best effort is:

I'm working on (tryapl) problem 2018 #3 ... I understand the concept, but I'm at bit of a loss for how to produce the exact output the system is looking for.

@FawnLocke Ok, thanks.

What does it mean in dyalog when a matrix is displayed with a little "+" in the lower left, when boxing is enabled? (currently with style=max)

So I guess maybe I'm getting extra confused by scan when I'm scanning using a non-commutative function.

But it didn't do quite what I expected and then I got sidetracked.

@dzaima Yes, I'm sure I don't have a sense yet of when to use it. This came up in the context of (tryapl) APL problem 2018 #1, where you're computing which skyscrapers you can see. So what I was trying to do was go over the list and find the places in the list where the value increased ...

@Adám I can work through it step by step ... and it makes sense, as long as I group things into all of those prefixes ...

The results of scan seem so obvious with +, and much less obvious to me in many of these other cases. I'm going to have to figure out how to get an intuitive grasp on it so I can solve problems with it.

@Adám Yes, that makes it explicitly clear. I just have to wrap my head around it. Thank you and @FawnLocke as well for helping me walk through it. I'll work on it a bit more and hopefully internalize this.

@Adám Story of my life with APL ;)

(Since I assumed the right hand argument is the result of the previous iteration)

5 > 1

In other words, I would have expected that the next step would be ...

Why is there a 5>5 there if we're going from right to left, and the previous result was 1 (due to 5 > 2 ==> 1) ?

Which comparison results in the 0 in the middle of the result 5 0 1 ?

{⎕←⍺ ⍵ (⍺>⍵)⋄⍺>⍵}\5 5 2

My attempts like this aren't helping:

I have to work on this some more. I'm not seeing it.

And when examining that output, it doesn't look like it's going right to left.

,\5 5 2