So it is important to know what's an operator and what's a function. User defined operators are pretty rare, and the built-in ones have a certain "look" to them. Most are "dotty", .¨⍨⍤⍣⍠ or "slashy" /⌿\⍀. Three are "boxy" ⍠⌺⌸ (but ⌹ is not an operator). The rest are a bit arbitrary: ∘ is easy to remember as that is TMN function composition. Remains: @⌶&
And it is of course also important to know which operators are monadic, and which are dyadic. You'll get to know them all soon enough. Don't worry.
@ASCII-only You'll increase your vocabulary as you go along. Let me know when you're ready to learn about user defined functions.
@ASCII-only Many (but not all) built-in functions use a default left argument when called monadically. It is good practice to write your own functions like that too.
@ASCII-only Yes. I wanted you to pick that up. Nice!
In fact, you can specify a default left argument by assigning to ⍺. That statement is only evaluated if the function was called monadically. E.g. root←{⍺←2 ⋄ ⍵*÷⍺}
As you can see, multiple statements are separated by unbreakable diamonds ⋄
@ASCII-only Well, you can also just use multiple lines, but that requires an editor. The REPL can't (easily) do that.
@ASCII-only I think that's basically it for a brief intro. You should be well equipped to benefit from APL cultivation now. I'm here to assist of course. Try solving something easy like testing if an argument is prime!
@ASCII-only Yes, but not the assignment to a name. However, when you gain a little familiarity with this, you should look into tacit APL. It is often much shorter, and doesn't have braces.
The most basic form of going tacit, is by just replacing ⍺ with ⊣ and ⍵ with ⊢. Those two "tacks" are simple functions which return the argument the finger points at. And the braces go, of course.
But there is an important principle. The rightmost part of a tacit function must be a function, not an array.
So we have to swap the arguments of ↑ to make this work: ⊢⊂⍨(⍴⊣)⍴1↑⍨⊢
@ASCII-only And that's the answer. There's a bit more to know about tacit functions, but this conversion method often works. Go ahead and post your first APL answer!
Given 3 integers, determine the lowest possible base for the first two integers to multiply into the third. If you think of the Answer to the Ultimate Question of Life, The Universe, and Everything, 6 * 9 == 42, is true in Base 13.
The inputs can include any numbers whose digits use the characte...
@ASCII-only I adjust the byte count to be character count and replace the word "bytes" in the code golf template with [bytes](https://codegolf.meta.stackexchange.com/a/9429/43319 "When can APL characters be counted as 1 byte each?")<sup>[SBCS](https://github.com/abrudz/SBCS ".dyalog files using a single byte character set")</sup>
@Sherlock9 Well, thanks. I still think it's unclear in the challenge whether it's only the 2 numbers taht need to be base-converted, or the expected result as well
Write a program or function that outputs this exact text, case-insensitive:
A, B, C, D, E, F, G,
H, I, J, K, L, M, N, O, P,
Q, R, S,
T, U, V,
W, X, Y, Z.
(Based on the alphabet song that many American kids learn to help memorize the alphabet, though edited for more compressibility.)
The outpu...
In the examples in the Dyalog chm help file on drawing simple lines in a form, I drilled down into all of the various options you can place on a Form window creation and could not find a way to turn off the auto-scaling. That is, when I resize the Form, I don't want any object drawn within it t...
@ngn normalization can easily go wrong, and it's standard practice on PPCG to allow different types of output, and I often switch between tradfn, ⎕←, dfn
@ngn no idea how many, but many challenges allow choosing ⎕IO, ascii-art may allow trailing spaces, matrices usually can be represented both as matrices & vector vectors, some allow floating-point imprecision, challenges taking a set amount of inputs may benefit from argument order - A f B, B f A, f A B, f B A. really the only things safe are challenges with a single number input & output, both being unrelated to ⎕IO
@Sherlock9 that's cruel to those who just want to check your solution, and maybe cruel to yourself when you eventually forget about that particular challenge :)
@ngn Which is why it's also good practice for the challenge writer to put test cases in their challenge and the solution poster to run the test cases in that order so they can check it :)
for me it boils down to this: is there any reason for doing the actual≡expected check manually? if there is (e.g. tradfn handicaps, too flexy output fmt, etc) then fine, i have a reason not to automate
@Sherlock9 you know, when we have an operator like ⍣, if we write operand0⍣operand1 arg and operand1 arg1 are both arrays, they would strand. so instead we write (operand0⍣operand1)arg or the golfier: operand0⍣operand1⊢arg
Turning the short version in your comment into a TIO link looks like it's going to be tricky. Not sure how to test 1 through 30 here tio.run/##SyzI0U2pTMzJT///36j6Ue/…
@dzaima … because that was one of the ideas that was considered within Dyalog. It has the benefits of being really simple (to explain) and can also work to create multi-line trains.
I posted that solution at last, @ngn. I don't think this explanation's very good, but that's partly because I don't know how to explain ⍎¨⍕, so I guess I don't really understand it
APL (Dyalog Unicode), 61 bytes
{3⊃⍺=10⊥⍵(⊥⍣¯1)×/2↑⍺:⍵⋄⍺∇⍵+1}∘2
Try it online!
Thanks to Adám for the help and to Sherlock9 for base conversion.
Write a program or function that outputs this exact text, case-insensitive:
A, B, C, D, E, F, G,
H, I, J, K, L, M, N, O, P,
Q, R, S,
T, U, V,
W, X, Y, Z.
(Based on the alphabet song that many American kids learn to help memorize the alphabet, though edited for more compressibility.)
The outpu...
In the examples in the Dyalog chm help file on drawing simple lines in a form, I drilled down into all of the various options you can place on a Form window creation and could not find a way to turn off the auto-scaling. That is, when I resize the Form, I don't want any object drawn within it t...
