The Nineteenth Byte

@Fmbalbuena In Worksheet mode, the output displays next to your code (it's not part of the code). If you want, you can wrap those expressions in println() and it'll show up in the console like this

Unrelated String

i finally figured out how to index into a Seq so that's _.intersect("aeiou")(0) for 23

user

Ooh, didn't think of that one

Unrelated String

12:36 AM

was wondering what all those methods about PartialFunctions of Ints were about :P

user

@user (this should be _.find("aeiou".toSet) actually)

@lyxal you need '

thank you scastie

Nice, what was your solution?

lyxal

12:36 AM

val f: Seq[Char] => Char = _.filter((x: Char) => "aeiou".contains(x))(0)

but that's not the point here

wait

oh

that's a horrible way of showing the result

Fmbalbuena

@user Impossible

lyxal

I thought it was saying like the type of the result is scala char and not showing me the result

user

Here's a horrid solution:
_.collectFirst {
  case c@('a'|'e'|'i'|'o'|'u') => c
}

Unrelated String

lmao

user

@Fmbalbuena The ... was just a placeholder for all the other comparisons to vowels

Did you see this? That's what an isVowel function might look like

Fmbalbuena

12:39 AM

@user Impossibleee

user

Dude are you just trolling rn

Fmbalbuena

@user Ok, I will not troll

user

Thanks

Fmbalbuena

Last Impossible, Sorry

Unrelated String

:|

Fmbalbuena

12:41 AM

Ok, I have a problem

user

CMS: Another easy one, find the average of a nonempty list of numbers (Scastie) (this is again mainly to show the stdlib)

@Fmbalbuena Yes?

Fmbalbuena

CMS: Print "Hello, World!", but you can't use theese characters "He, 0123456789"

Unrelated String

l=>l.sum/l.length?

user

Yup, though you can do .size too

Unrelated String

ah

user

12:45 AM

I think the .length is for Java people, it annoys me that there's two methods

Unrelated String

lmao

user

CMS: Sum a list without using sum. Feel free to use recursion

Fmbalbuena

@user for loop, But I can't learn Scala

hyper-neutrino

oh it's l.sum?

emanresu A

@user Quick question: How to make an array of ints?

lyxal

12:46 AM

@user Why doesn't val f: List[Double] => Double = _.sum/_.size work?

user

Why not? There are easier ways than for loops, but if that's what's familiar to you, you can try this

@emanresuA Array(1, 2, 3) works, but I'd recommend using a List (List(1, 2, 3))

Unrelated String

@user ...and Seq only provides size; length is just a List thing?

user

@lyxal Because the second _ means you're taking two arguments and you want the size of that second argument

hyper-neutrino

oh scastie is one of those editors that groups characters together into tokens like <= into ≤

cool

Fmbalbuena

@user Uh, For loops and if statements?

user

12:47 AM

@UnrelatedString You know what, I honestly don't know

@Fmbalbuena If statements are pretty simple too, just do if (cond) { thenDoStuffHere() } else if (otherCond) { blahblahblah } else { blahblah }

emanresu A

@user _.reduce((a,b)=>a+b)

Fmbalbuena

@user for loops?

Unrelated String

and it's not like there's a second interface that gives List a length

it's just kinda there

user

@Fmbalbuena for (elem <- lst) { dostuff }

lyxal

@user so then how do I refer to the first argument if the lambda definition doesn't specify arguments?

emanresu A

12:48 AM

How do you permalink scastie?

user

@UnrelatedString Oh, it might be an extension method

Fmbalbuena

@user Do you mean DLosctuff?

user

@lyxal ...You don't

Unrelated String

@emanresuA (a,b)=>a+b -> _+_

Fmbalbuena

@user elem <- lst?

user

12:49 AM

@emanresuA Hit save and copy the URL

@Fmbalbuena Yes, the <- is like Python's in

emanresu A

scastie.scala-lang.org/Y855fwPQTSyRZMeAzqHNWg

Or JS's of because JS's in makes no sense

lyxal

@user so then what's the point of the template val f: List[Double] => Double = if it doesn't specify any named arguments and I can only use _?

Unrelated String

@lyxal it's just generically here's something to set your lambda to for the test harness below

DLosc

@lyxal The cognitive dissonance is fantastic X^D

Wezl - y izl

@user x=>x./:(0)(_+_) (Not sure how to use this ternary operator)

user

12:50 AM

@emanresuA Nice find, there's quite a few variations on that: _.foldLeft(0)(_+_), _.fold(0)(_+_), _.reduceLeft(_+_), _.foldRight(0)(_+_), _./:(0)(_+_), _.:\(0)(_+_) (those last two are deprecated)

Fmbalbuena

val inputlist: [2, 2, 4, 8, 16]
val f: 0
for (elem <- inputlist){
  f: f + elem
}
print(f)

Not working

user

@Wezl-yizl It's not a ternary operator, it's just a curried function. It's deprecated now because people don't like the symbols, but it's equivalent to x.foldLeft(0)(_+_). You'd use it like (0 : x)(_+_) in real code (the fact that /: ends in : makes it right-associative)

@Fmbalbuena : is used to show the type of a variable. Here, you don't need to do that, Scala infers those types for you, just use = instead. Also, list literals have to be written as List(2, 2, 4, 8) instead of [2, 2, ...]

And f needs to be a var so that you can modify its value (vals are final, you can't change their value)

Fmbalbuena

inputlist = [2, 2, 4, 8, 16]
val f: 0
for (elem <- inputlist){
  f = f + elem
}
print(f)

user

And you can turn f = f + elem into f += elem, both are pretty much the same here)

Fmbalbuena

Still not working

user

12:54 AM

val inputlist = List(2, 2, 4)
var f = 0

Try that

lyxal

What's wrong with my lambda definition here:

val f : List[Int] => List[Int] = _.scan((a, b) => a + b)

It's gives an error:

Missing parameter type

I could not infer the type of the parameter a.
Missing parameter type

I could not infer the type of the parameter b.

when called on something like:

f(List(1, 2, 3, 4, 5, 6))

Fmbalbuena

:60320061 val inputlist = List(2, 2, 4)
var f = 0
for (elem <- inputlist){
  f += elem
}
print(f)

OldSandboxPosts

Sandbox posts last active a week ago: Truncatable Primes, Ragged Matrix, Ragged list addition, Trap the persistent hero in a maze

lyxal

nvm it should be

val f : List[Int] => List[Int] = _.scan(0)(_+_)

because it needs the initial value

user

Ninja'd

I spent a solid 30 seconds trying to figure that one out

Also, I'm sorry but I need to go have dinner now, I'll just leave a couple CMCs here

CMC: Sort a list of numbers by how many digits they have in binary (with the leading 0's trimmed)

CMS: Cartesian product

emanresu A

1:10 AM

You've got me to do this already

user

CMS: Convert base A to base 10, CMS: Convert base 10 to base A

emanresu A

@user for(a<-_;b<-_)yield List(a,b)

scastie.scala-lang.org/CV5SuDx0Q3qG3NWJ2geQiA

Fmbalbuena

CMS: Ackermann function with finite recursion

emanresu A

@user That's just plain sorting

Fmbalbuena

@emanresuA I have a issue, See DSO repo

lyxal

1:21 AM

@user _.sortWith(_.toBinaryString.size < _.toBinaryString.size)

Wezl - y izl

* Wezl went to dinner in the middle of LYAL and nobody minded so

emanresu A

@Fmbalbuena Fixed.

Fmbalbuena

@emanresuA thanks, I will use this one time.

Unrelated String

so from base 10 is pretty straightforward but for to base 10 does Seq not supply any kind of unfold? :(

...actually why would that be in Seq

time to actually search

wait no it is in Seq

user

1:45 AM

Yes, you can use unfold with Option.when

Unrelated String

...wish i'd seen when before writing List.unfold(_)(n=>Some(n%10,n/10).filter(_+_>0))

user

I think I have a couple answers that use it if you want to try beating me

@UnrelatedString i mean this is pretty good

@lyxal try sortBy

lyxal

@user that requires some sort of ordering though

And I couldn't get it to work

Unrelated String

it is cool that multiple arguments genuinely are just single tuple arguments

user

@emanresuA Yup, you can even do ‘yield a->b’

@UnrelatedString ahahaha

emanresu A

1:47 AM

@user Hm

user

@lyxal ???

It’s just .sortBy(.toBinaryString)

Fmbalbuena

@emanresuA github.com/chunkybanana/do-stuff-online/issues/4

user

@UnrelatedString that’s a scala 3 feature and it’s not actually a single tuple, it’s just sugar for pattern matching on the tuple

Unrelated String

oh

emanresu A

I have too many tabs, o/ while I clean up

Unrelated String

1:49 AM

still cool

and lets you pretend it's the same thing

user

A funct That takes a tuple would be ((Int),(Int))=>foo whereas a function with two args is just (Int,Int)=>foo

@UnrelatedString definitely

Unrelated String

@emanresuA do you not just close everything to the right of an arbitrary tab whenever it gets to like 100~200

user

It gets to 100 for you? :o

lyxal

@user you seem to be missing some backticks there

Wezl - y izl

all my tabs are important and special to me. I would never do that to my children

user

1:51 AM

I switch to a new window when I can’t read the names anymore

Wezl - y izl

except for the TNB ofc

user

@lyxal lol yeah it’s _.sortBy(_.toBinaryString)

Unrelated String

@user firefox enables me by having a high minimum width }:-)

user

Forgive me, I’m on phone

lyxal

@user it was complaining about some sort of argument application or something

user

1:52 AM

Hrm

What message did you get?

lyxal

I don't remember exactly and I don't have my computer with me rn

But it was saying something about ordering or smth

user

Oh ok

@lyxal oic you need.size

_.toBinaryString.size, because you can’t compare strings

Razetime

oh hey it's da Scala time

user

Lol it’s almost over I think

Unrelated String

lmao

lyxal

1:54 AM

LYAL lasts for 24 hours

user

CMS: All sublists of an infinite LazyList

lyxal

We partying for the next day gamers

Fmbalbuena

@user LazyList?

user

@lyxal oh cool, i can post more tomorrow

@Fmbalbuena look it up, i can’t link now because mobile weak

Fmbalbuena

@user mobile weak

Razetime

1:56 AM

@user is scala-algorithms.com an up-to-date source?

user

CMS: Make a LazyList of fibonacci numbers

emanresu A

@UnrelatedString You can do that?

user

@Razetime I have no idea, I suppose so?

Unrelated String

right click?

emanresu A

Oh

Did not know about that

Thanks

user

1:57 AM

Even if it’s old it shouldn’t be completely broken

emanresu A

It took ~15s to close lol

user

You did this to yourself lol

emanresu A

I did

Fmbalbuena

@emanresuA Can you fix and I will double the DSO posts.

Razetime

@user there gotta be some proper place to read up to date scala docs

Unrelated String

1:59 AM

took me this long to realize it outputs backwards lmao
not that that's necessarily a problem

Razetime

like cppreference.com

user

@Razetime oh yeah the scala website itself has a book

emanresu A

@Fmbalbuena That is another bug

Razetime

mmkay

Fmbalbuena

@emanresuA I will review you, Then i will post every bug.

user

2:01 AM

in Scala, 8 hours ago, by DLosc

It's true that the Scala book does start off with a bunch of "Scala's type system has this great feature," which doesn't mean anything if you don't know a lot about type system theory (I don't). It might be best to start from this point instead.

emanresu A

It was missing a bytecount update in a different place

Unrelated String

anyhow i noticed because i threw together val f:Int=>List[Int]=n=>if(n>0)n%10::f(n/10)else List() about which i'm wondering if there's any way to golf the signature since it seems to demand it

emanresu A

@Fmbalbuena Fixed.

Unrelated String

would beat List.unfold(_)(n=>Option.when(n>0)(n%10,n/10)) without it

Wezl - y izl

@user 0#::1#::f.zip(f.tail).map((a,b)=>a+b)

Fmbalbuena

2:04 AM

@emanresuA easy fix, I will review again

Unrelated String

tried to hack together some kind of fix combinator but it still complained that it couldn't infer

user

@UnrelatedString yeah scala doesn’t have hindley milner or anything, and recursive stuff needs type annotations (even when the compiler could theoretically infer it)

lyxal

why does val LL : LazyList[Int] = 1 #:: 2 #:: 3 complain that value #:: is not a member of Int?

user

@Wezl-yizl nice!

Unrelated String

rip

@lyxal you probably need a LazyList on the right

user

2:06 AM

@lyxal because 3 is an Int. Try replacing it with 3 #:: LazyList.empty

Wezl - y izl

@lyxal I think that means that it's calling the #:: method on 3, which doesn't have that method

@Wezl-yizl totally not taken from the example in the docs

user

Good night all, I’m happy to see people interested in Scala o/

Unrelated String

o/

emanresu A

@Adám BQN's JS is node.js which is difficult to run in the browser

Wezl - y izl

why would I not be interested in a language with xOrElse! functions :P

Fmbalbuena

2:09 AM

@emanresuA 2 posts, 4 posts if you fix This bug

@emanresuA feature? [ should be infinite loop, WRONG [ is [] but [] is NOP

emanresu A

What do you mean?

Fmbalbuena

@emanresuA Try it online! (Pretend the footer code is empty)

Razetime

@emanresuA BQN.js is not node.js.

It's perfectly embeddable in any static site, I think you got it wrong.

I even wrote my own online repl for it: razetime.github.io/bqn-repl/

emanresu A

Oh. I had this bqn.js which clearly is node, where's the one runnable in the browser?

@Fmbalbuena I don't care. That's undefined behaviour.

Fmbalbuena

@emanresuA ...

Razetime

2:16 AM

@emanresuA mlochbaum.github.io/BQN/doc/embed.html

emanresu A

[ is not, and never was, a valid BF program.

@Razetime Oh, ok. Will add.

Fmbalbuena

@emanresuA then You should raise error

Razetime

Btw @Bubbler also had a "Try in Browser" thing that was supposed to have offline interpreters for everything

might wanna ask him

emanresu A

BQN works

And permalinking BQN also works, to my surprise

Oh wait of course it works, I just stole the permalinking code from Vyxal

ta Radvylf srik su shilani

2:49 AM

I'm considering buying a really cheap cloud server to act as a fallback for my hardware one

That way NP/SP, RTO, OSP, etc. will have all of the reliability of the ✨cloud✨, but without the ridiculous costs

lyxal

3:00 AM

So remember how I said swimming pools are organised chaos consisting of individual groups of order? Well I think that term also applies to shopping centres

Although they are more annoying than public swimming pools though

caird coinheringaahing

Less likely to get peed on tho

lyxal

More likely to have your toes run over by people or by a trolley

caird coinheringaahing

What kind of swimming pools are you going to where there aren't any trollies smh

Unrelated String

smh

emanresu A

smh

caird coinheringaahing

3:15 AM

Here's a question: is it possible to define a sequence of functions \$f_n : N^n \to N^{n-1}\$ such that none are bijective, but the function \$f = f_1 \circ f_2 \circ \cdots \circ f_n\$ (or, in a looser fashion, in any order) is bijective?

(Assuming \$n \ge 2\$)

emanresu A

smh Mathjax doesn't work in chat

caird coinheringaahing

It does for me :P

I think no: consider an inductive argument, we'd need \$f_k \text{ bijective} \implies f_{k+1} \text{ bijective}\$, and that \$f_1\$ is bijective, thus a contradiction

emanresu A

Userscripts?

caird coinheringaahing

Yeah

@cairdcoinheringaahing But, this assumes an inductive proof

emanresu A

After looking at the code for oK, I'm not going to try adding it to DSO

It doesn't have a single run function, it takes inputs in K form and requires a seperate file to convert, its error catching code is painful...

oic, TIO uses the repl.js file which is node.js :(

Nitrodon

3:30 AM

Did I miss the LYAL?

lyxal

Some stores have "back to school" sections where they have things like stationery, backpacks, etc etc. I like to stand in front of these displays and laugh condescendingly at the nerds that have to partake in buying objects from this display because I'm a uni student

@Nitrodon LYALs go for 24 hours

So no

caird coinheringaahing

@Nitrodon Nope, lasts from midnight UTC to midnight UTC

att

3:44 AM

@cairdcoinheringaahing Let \$\{e_{k,i}\}\$ be an enumeration of \$\mathbb N^k\$ for \$i=0,1,2,...\$, and define \$f_k(e_{k,i})=e_{k-1,i+1}\$ for \$2<k\le n\$, \$f_2(e_{2,i})=e_{1,\max(i-n+2,0)}\$. \$f_k\$ where \$k>2\$ are not bijections because nothing maps to \$e_{k-1,0}\$, and \$f_2\$ is not because \$e_{2,0}=...=e_{2,n-2}=e_{1,0}\$, but it's easy to see that \$f_n\circ...\circ f_2\$ is, mapping \$e_{n,i}\to e_{1,i}\$ for all \$i\$

I don't see mathjax either so I'll have to trust you can :')

caird coinheringaahing

@att I don't think that shows \$f_n \circ \cdots \circ f_2\$ is a bijection does it?

att

For brevity let's call \$f_n\circ...\circ f_2\$ \$f\$
\$f\$ is surjective: for all \$e_{1,i}\$, \$f(e_{n,i})=e_{1,i}\$. \$e_{n,i}\$ exists.
\$f\$ is injective: suppose \$f(e_{n,i})=f(e_{n,j})\$. Then \$e_{1,i}=e_{1,j}\$, which can only happen if \$i=j\$.

It might be easier to see if you consider \$e_n\$ as a bijection between \$\mathbb N\$ and \$\mathbb N^n\$

PyGamer0

4:20 AM

@user is this for vyxal v3 :P

@emanresuA ngn/apl ?

oh DSO has BQN

also did we get another spam wave O_o

emanresu A

4:45 AM

@PyGamer0 Yep! And surpisingly, permalinking works even with glyphs

@PyGamer0 JS apl implementation, works surprisingly well

lyxal

5:01 AM

@PyGamer0 ... maybe ...

emanresu A

6:12 AM

Ok, I'm gonna try and compile ngn/k to wasm. Wish me luck!

PyGamer0

7:58 AM

@emanresuA were you successful?

emanresu A

I have a wasm file but no idea what to do with it.

o/

New Posts

8:32 AM

0

Q: prime aluminium industry

prime aluminium industry is the popular aluminium suppliers in pakistan. You can see list of aluminium price in pakistan. Its is providing the premium aluminium with latest technology of thermal break. Our products are: aluminium windows aluminium doors You can find us: aluminium windows design i...

primes

emanresu A

Butter?

Was there a challenge to interpret !@#$%^&*()_+

Sandbox Posts

8:56 AM

0

A: Sandbox for Proposed Challenges

Find the index of the matching parentheses for each character The challenge is simple, find the matching parentheses for every one of the parentheses in a given string input E.g. ()()() -> [1, 0, 3, 2, 5, 4] Always start with the ending parentheses index before the starting parentheses, which is...

Adám

@emanresuA BQN errors give [object object]

@emanresuA Is there a way to link to a language on DSO, like tio.run#apl-ngn?

emanresu A

9:34 AM

@Adám Exactly the same :P - dso.surge.sh/#ngn-apl

Adám

Neat.

emanresu A

Wow DSO is horrible on mobile

@Adám I’ll see if I can get them to print the actual errors tomorrow

lyxal

@emanresuA make the svgs smaller

emanresu A

They’re not svgs

They’re icons

lyxal

Then make the icons smaller

emanresu A

9:38 AM

I’ll see what Ican do

Adám

@emanresuA Now added to apl.wiki/Running_APL

emanresu A

Ok, thanks

@lyxal I need a lot of space for the language selection dialogue but I’ll see what I can do.

lyxal

Switching the language doesn't update the byte count if there's a change from custom bytes to standard bytes or vice versa

Adám

@emanresuA Shouldn't ngn/apl be listed as "APL (ngn)"?

@emanresuA You could do with a font-family styling for input and output.

emanresu A

@lyxal hm, okay. If you can put it on the repo I’ll fix it tomorrow

@Adám that’s changing one line of json, sure

@Adám wdym?

Adám

9:48 AM

@emanresuA Since you're dealing with languages that tend to use "funny symbols", you should force something like DejaVu Sans Mono.

emanresu A

@Adám Okay.

@lyxal after some investigation that appears to be lag when loading the bytecounter.

lyxal

@emanresuA when going from standard to custom, but not the other way around

PyGamer0

@emanresuA yeah

lyxal

Type something in risky and then switch to in floop

emanresu A

I know

Also, opinions on this mobile design:

Adám

10:01 AM

Cramped but works. How about removing "DSO"?

emanresu A

True

o/, need sleep

Adám

Nah, sleep's overrated.

lyxal

Don't listen to Adám, sleep is for gamers

Adám

I'd remove "Select language too, Or maybe make it just:
Lang: [Ultrarisky________↕] 🔗
▶ 🔗 🏅 M↓ </>

With the bottom icons spread evenly across, and the input field adjusting its width dynamically to fill the width.

New Posts

10:45 AM

0

Q: Should graphical-output challenges accept straight up image files by default?

I've often seen some questions tagged graphical-output and kolmogorov-complexity that have some answer being image files, and they are often disagreements in the comments. examples: Swiss flag (PNG) Swiss flag (GIF) Iceland flag Carpet an airport Minecraft tool Super Mario RGB colour grid Here's ...

discussion rules kolmogorov-complexity graphical-output

Transcript for