the k tree

ngn

07:03

thanks to @bubbler's nomination, k is now:

2

6

Q: Language of the Month for August 2021: K

In accordance with our meta agreement, since one candidate received more votes than the others, we have a new featured language! Throughout August 2021, our Language of the Month will be: K What's a Language of the Month? See the meta post for nominations. In short, during August, those who wis...

4

@Bubbler i can't contribute much time but can i offer my rep for you to spend as you see fit? it should be enough for at least 500/day in bounties

A username

Is there a simple way to map a function over a list?

lyxal

'

{}'<list>

A username

Oh ok

lyxal

At least, that's how I'm doing it

Razetime

yep that's right

if you're using arithmetic ops only, you can do {}@ as well

lyxal

07:17

Here's the start of my attempt at a horribly cursed fizzbuzz: {("Fizz";"Buzz")*(0=(3!x;5!x))}'1+!100

A username

So is ; syntax sugar for newlines?

lyxal

no

A username

In strings I mean

lyxal

> Mixed-type lists are enclosed in () and each element should be separated by a semicolon:

(1 2 3;"food";`b)

Razetime

; and newline both work as statement separators, yes

lyxal

07:18

oh nevermind kekw

source for the quote

A username

I is using that too

PyGamer0

so is {} a dfn?

Razetime

Welcome @PyGamer0

@PyGamer0 yes, very similar

A username

It's like JS but less cursed

Razetime

@PyGamer0 k has variadic dfns though

x,y,z are the default first, second and third arguments

PyGamer0

07:19

@Razetime so multiple arguments can be passed?

Razetime

@PyGamer0 yes, func[arg1;arg2;arg3]

there are 3 main ways to apply a function

func @ arg applies a single argument to a function

lyxal

@Razetime how to keep only truthy items in an array?

Razetime

func[arg1;arg2;...] can apply any number of arguments, called an M-expression

@lyxal {x}#array

where # is used as filter

lyxal

that...doesn't seem to work

Razetime

and the third way is dot-apply: func.array

lyxal

07:22

tio.run/##y9bNz/7/…

PyGamer0

ok how does the fibonacci seq program look like?

Razetime

there's a lot of ways to do fibonacci

give it a try first and I'll tell you how to improve it

@lyxal so this also works like APL's filter

lyxal

I barely knew what I was doing with my APL fizzbuzz

so what makes you think I know how APL's filter works?

Razetime

ok so lemme teach that then

what happens when you repeat a thing 0 times

lyxal

empty

nothing

nil

PyGamer0

07:25

how do i give names for functions?

Razetime

it ceases to exist

lyxal

@Razetime that's what i said

Razetime

@PyGamer0 functions and vars are declared using <name>:<value>

@lyxal yes, but there's no nil value assigned is what I'm getting at

it's just removed

lyxal

oh

Razetime

so a filter also works as a replicate

so you need {~~x}#array

lyxal

07:26

very nice

PyGamer0

uuuh if statements?

$[]??

lyxal

@PyGamer0 where we are going, we don't need if statements ;)

Razetime

@PyGamer0 yes, that's the one

you'll rarely need if statements unless recursion

PyGamer0

@Razetime how do i define the condition and the body

f:{$[x=0;1]}

is that right?

lyxal

erm, why is () considered truthy when logically or'ing?

wait better question

why is () considered greater than something like 3?

how do I make ()|3 or ()&3 return 3?

@Razetime ?!

Bubbler

07:38

@lyxal What you're seeing is vectorized max/min

lyxal

an empty value is greater and less than 3?

oh right

it's vectorising over an empty list

Bubbler

You have a list on one side and a scalar on the other side. The scalar side is mapped to every item in the list

Yes

K doesn't have duck-typing-y falsiness, so you may need to think something entirely different to get what you want

@ngn Thanks for the offer, but I believe I can afford the LotM bounties myself.

@PyGamer0 Almost correct, but you need else branch too

lyxal

let's go first K fizzbuzz of mine

As single line: {}`0:{$[1=#x;$-1#x;1;`c$1_x]}'{x,{~~x}#,/("Fizz";"Buzz")*0=(3;5)!'x}'1+!100

Bubbler

Nice job

PyGamer0

@Bubbler how do i print the argument?

Razetime

07:52

K will auto print return values

PyGamer0

f:{$[x=0;1;f x-1]} so far

Razetime

unless you terminate the line with a semicolon

Bubbler

1`0:x

Razetime

@PyGamer0 yes, this is a correct function, now call it

PyGamer0

@Razetime it always return 1

Razetime

07:54

oh, it's a recursive program

nvm you're doing the wrong thing

@PyGamer0 you're missing one step

PyGamer0

@Razetime what

Razetime

yep, this is a factorial

what's the elementary operation in the factorial

PyGamer0

@Razetime multiplication

Razetime

you have no multiplication in your function

welcome @yiyus

PyGamer0

f:{$[x=0;1;x*o x-1]} works

Razetime

07:58

correct

there's a -2 bytes possible

can you find it?

PyGamer0

08:21

f:{$[x=0;1;x*o x-1

? @Razetime ^

Bubbler

No, K isn't a golflang like Vyxal, so it doesn't have bracket autocompletion or something like that

PyGamer0

sooo how?

Razetime

08:45

hint: truthy and falsy values

A username

Hi

Fiddling w/ stuff

Razetime

hello

what's the stuff

A username

How do you repeat a string?

Razetime

n times? like Hello → HelloHello?

A username

Yeah

Razetime

08:56

,/2#, comes to mind

A username

How does that work and how do I use it?

Razetime

just plop the string on the right

it makes a singleton array, repeats its elements n times, then joins the array

A username

And the number on the left? Ok

Razetime

no, no number on the left

you have to change the 2 to what number you need

A username

O

Razetime

08:58

as

A username

Thanks

Razetime

as a function: {,/x#,y}

or {(x*#y)#y}

A username

Ok

Just warning you: I have four nested functions right now...

Razetime

well, I can help out dw

just make sure your thing works

A username

How do I get a single backslash in a string?

Razetime

09:03

same as C

double backslash

A username

But...

Or is that just prettyprinting?

Razetime

that's the prettyprinting

A username

Ok

Razetime

see: Try it online!

A username

Gotcha

Razetime

09:13

really, the pretty printing is done such that you can always paste returned values back into a K program

A username

09:36

How do you join a list into a string without a separator?

Razetime

,/

A username

Thanks!

90% of the way there

ngn

@Bubbler the more bounties the merrier

for instance, i think there should be a BIG bounty for anyone who manages to outgolf @coltim at least once this month :D

@Ausername you can reshape atoms too: ,/n#," " -> n#" "

A username

@ngn Thanks! I'll think about golfing it once it's working :p

ngn

@Ausername that newline after $[ looks suspicious

A username

09:46

I know, newlines are statement separators

But it appears to be working

Razetime

but it is sus

you do not want your code to be ejected

A username

Finally!

Razetime

woot woot

A username

Implementing it wasn't too hard - I basically copied my reference implementation :p

Razetime

copying from different languages doesn't work too well in K

but you managed it, nice

now to improve it

A username

09:58

I'll leave that to you guys.

Razetime

(";"\x) → ";"\x

K is right to left

A username

Oh cool

Razetime

one more tip: "<char>" is a single character, not a string

so you can do n#" " instead of ,/n#," "

A username

Oh ok

That be cool

Razetime

characters are also integers in K

this means you can check equality with ascii values

A username

10:02

Oh that's good

Can you do the same with the string repetition trick?

Razetime

nope, chars are still a different type

A username

Ok

Razetime

you'll need to spend extra bytes casting it back

so "\\"=x can become 92=x

A username

Ok

Doing all of that

Razetime

{,/x}' can be just ,/'

likewise "/"=x can be 47=x

(k-1)=x becomes x=k-1 due to right to left

A username

10:06

I actuallyhadthat onealready

One moment

Razetime

a large part of good K programming, and in turn, golfy K programming is removing conditionals

,/k#,$[x=k-1;"_";" "]

there is a pattern here, can you spot it

A username

The last one is a _, the rest are spaces
Oh I se

e

Una moment

Heres what I have so far

Razetime

you don't need a lot of ,/s there

A username

Ok

Razetime

{k#" "}'!k can be converted to (k;k)#" "

A username

10:13

@Razetime I tried this

but it didn't work

Razetime

ok lemme show

we have:

,/k#,$[x=k-1;"_";" "]

remove the ,/ and ,

k#$[x=k-1;"_";" "]

A username

Yep

What now?

Razetime

now, if x=k-1 is zero then we get an underscore

if it's 1 we get a space

A username

Yeah

Oh indexing?

Razetime

k#"_ "@x=k-1

A username

10:15

Nice!

Razetime

you can do this with most of the 2 branch conditionals

lemme add my golfs

A username

Cool

That should get it down to sub 200

Or not

But close

Missed some commas

Razetime

199 :)

A username

:)

Actually 197

Razetime

ah ok

A username

10:24

Since the f: isn't part of it

right?

Razetime

yep

A username

Is there a flat array operator?

Razetime

since the enormous if is basically checking x against a bunch of values

A username

Because that could save a few more bytes

Razetime

@Ausername flatten?

A username

10:24

Yes

Razetime

like,abitrary levels of nesting?

,// flattens till fixpoint

which would work

A username

Just flattening one layer is fine

Razetime

then ,/ is enough

A username

Ok

195

Razetime

you don't need to join on newlines

since 2d array is allowed as output

A username

10:29

Oh yes

I allowed that

Razetime

the io verb will insert newlines automatically for verification

A username

184 because I also said input will only contain certain chars

Razetime

ah removing the final condition

A username

Actually removing the | condition 'cos it's a byte longer

A username

10:42

175 By wrapping the code for \/ in another function

Razetime

neat

A username

Doing the same with |- only saves one more byte :p

For vectorised reverse, is there anything shorter than {|x}'?

Razetime

' is an adverb

so you can just do |'

A username

Oh cool

Or not...

Razetime

so #, _ and other verbs need functions

but adverbs can directly take primitive

oh, you need monadic |

so do |:'

A username

10:52

Ok

And after a bit more stuff, 165

Razetime

once pygamer's bounty is over I'll award

A username

Ok

I think that's all the golfing I can do, at least for today.

Bubbler

11:14

@Ausername Impressive for the first day in K :D

ngn

13:22

can anyone solve it in 64 bytes or fewer?

ngn

13:33

ooh, 58 actually :)

Razetime

58?

holy

ngn

55 now (matching charcoal's score)

should i post it? or somehow try to bounty it per byte golfed?

Razetime

hm, it has to have math

or i'm missing a primitive

ngn

@Razetime what math?

i would say it's mostly structural primitives

Razetime

probably a base decode

ngn

13:47

no

Razetime

oh, then it's the second reason lol

Bubbler

I've been thinking of it too

Will try next morning

ngn

@Bubbler ok, i'm not gonna post it now then

in The Nineteenth Byte, 3 hours ago, by A username

When K loses to Python and C

^ this comment requires revenge :)

Razetime

i guess it does

but i can't really think of anything yet

too vim-pilled rn

chrispsn

i'm back on my native where itch. this is ~4-5x native speed {|\@[&*|v; -1_v:+\x; :; 1_!#x]}

@ngn it would be good if 0 :': was around the same speed as 0,-1_

ngn

14:09

@chrispsn yes, that's just a memmov and a store, but i need to improve my code for arithmetic in general to allow for ad-hoc optimizations like this

JohnE

ah, at first I thought it would just be a form of github.com/JohnEarnest/ok/blob/gh-pages/ike/examples/…, but I suppose the nasty part is the padding

dzaima

14:41

@ngn I've got 51 in BQN, but that's still kinda long considering it has actual matrix operations and a 2D raze

ngn

16:27

@ngn s/memmov/memmove/

ngn

17:31

@dzaima now i have 51 too

A username

19:31

Lol you guys are beating me 3x

and I completely forgot you can rename function inputs :p

It's actually quite similar to JS, but with more bulitins.

coltim

21:19

@Razetime my money is on =i

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