The Nineteenth Byte

Anonymous

20:02

@cat You've been doing a lot of good work lately with cleaning up older challenges. Thanks for your contributions. :)

cat

@Mego I try :)

Currently, the wording for the spec is:

Reverse the digits:
    61789372994
Sum the digits in odd positions:
    6 + 7 + 9 + 7 + 9 + 4 = 42 = s1
Sum the digits in even positions:
    1,  8,  3,  2,  9
Double each even digit:
    2, 16,  6,  4, 18
Sum the digits of each multiplication:
    2,  7,  6,  4,  9
Sum the result of the multiplication:
    2 + 7 + 6 + 4 + 9 = 28 = s2

If the result modulo 10 is 0, then the number is valid.

s1 + s2 == 70; 70 % 10 == 0, so 49927398716 passes the test.

But that's, as @MartinBüttner noted, kinda awkward. can I word the instructions better?

Anonymous

I would suggest a better wording if I had any idea how it was supposed to work

Anonymous

Brb wikipedia

cat

enwp.org/Luhn_algorithm

Anonymous

What about:

Anonymous

20:12

Reverse the digits, make an array:
    6, 1, 7, 8, 9, 3, 7, 2, 9, 9, 4
Double the numbers in odd indexes:
    6, 2, 7, 16, 9, 6, 7, 4, 9, 18, 4
Sum the digits in each number:
    6, 2, 7, 7, 9, 6, 7, 4, 9, 9, 4
Sum all of the numbers:
    6 + 2 + 7 + 7 + 9 + 6 + 7 + 4 + 9 + 9 + 4 = 70
If the sum modulo 10 is 0, then the number is valid:
    70 % 10 = 0 => valid

Martin Büttner

could collapse step 3 and 4 into "sum all digits"

that's probably less clear though

Anonymous

Yeah I went for clarity over shortness :P

Anonymous

Solutions should be golfed; specs should not

cat

I like @Mego's; here's what I came up with just now

Reverse the digits:
    49927398716
    61789372994
Sum the odd digits:
    6 7 9 7 9 4
    6 + 7 + 9 + 7 + 9 + 4 = 42 = s1
Two times each of the other digits:
     1 8 3 2 9
    2, 16,  6,  4, 18
Sum the resulting digits:
    2  1,6  6   4  1,8
    2,  7,  6,  4,  9 = 28 = s2

If the result modulo 10 is 0, then the number is valid.

s1 + s2 == 70; 70 % 10 == 0, so 49927398716 passes the test.

I think Mego's is likely clearer still

Anonymous

I think it's easier to keep track of the operations if you're only using a single array (i.e. not splitting the number into odd and even digits)

Åna

20:17

sup

cat

Hi @Åna!

Åna

Hey :)

quartata

Hello

cat

@Mego status-completed

El'endia Starman

Hallo. What brings ye to our domain?

Easterly Irk

20:22

hai

my computer died

my computer then undied

Åna

@EasterlyIrk this is useful

Easterly Irk

i lost all my ppcg stuff....

@Åna which, the undieing or my message?

i think both are

Åna

the undying

Easterly Irk

well, anyone have the PPCG Userscript link?

i needs

Martin Büttner

@EasterlyIrk it's still here, don't worry: codegolf.stackexchange.com

3

Easterly Irk

20:23

i losted all my extensions and then the userscripts

Martin Büttner

well...

Åna

That'll be a pain in the butt to fix :)

Easterly Irk

yah

and all my code, i just found out

4 years of python files, 1 year of julia, js, perl, and ruby.

wtf

brb rebooting to fix time machine

Doorknob

@poi830 Yeah, all syllables are CV

Åna

Not got a backup?

Easterly Irk

20:27

it seems to have deleted itself.

wtf

(-o

Åna

preferably on an external drive ;)

Easterly Irk

it was

@MartinBüttner :(

El'endia Starman

Normally, errands are tasks you have to do outside the house, and chores are things you have to do inside the house on a regular basis. What do you call one-time or infrequent "chores" like packing?

Easterly Irk

now os x can't open any files

wtf more

flawr

@EasterlyIrk That is why you unplug the back up drive again after you've finished doing the back up and store it in a secure place=)

Easterly Irk

20:33

i can't open a zip file.

Why god why.

El'endia Starman

Looks like it's time for a Windows machine? ;)

3

Easterly Irk

@flawr I did. Not kidding.

@El'endiaStarman My friend's windows machine died in fire, the wifi card melted.

and no.

flawr

It deleted itself while not running?

@EasterlyIrk Its windows' fault.

El'endia Starman

@EasterlyIrk Was that the fault of the machine? If so, probably wasn't Windows' fault. If not, then you can't even fault the PC.

Easterly Irk

@flawr i think it did while i was restoring the computer from it

@El'endiaStarman idk, but it looked epic when it died

Doorknob

20:34

@El'endiaStarman Or, he could upgrade to something even better instead... :P

flawr

Get some recovery tools, the files are probably still there if you haven't overwritten them.

Easterly Irk

yeah

planning on linux mint next

El'endia Starman

@Doorknob I will concede that Linux > Mac.

Easterly Irk

^

and windows < all

Doorknob

Isn't Mint based on Ubuntu?

flawr

20:35

Therefore windows < windows. Contradiction.

Åna

@EasterlyIrk this I must disagree with

Easterly Irk

@Doorknob no, debian

@Åna sowee, but the truth hurts.

El'endia Starman

@EasterlyIrk Lies hurt too.

3

Easterly Irk

yeah.

flawr

@EasterlyIrk It is based on ubuntu.

Easterly Irk

20:36

But that happened to be true.

Åna

heh

flawr

And ubuntu is based on debian.

Easterly Irk

From the linux mint about page:

flawr

@El'endiaStarman EVERYTHING HURTS.

Easterly Irk

> Based on Debian and Ubuntu, it provides about 30,000 packages and one of the best software managers.

Doorknob

20:36

Mint is based on Ubuntu, and Ubuntu is based on Debian, yeah

So Mint is just Debian plus some junk plus some more junk ;)

Åna

@flawr you should probably get that checked out

Easterly Irk

@Doorknob might try debian

quartata

Why can't we just all agree that Linux is the best OS and Arch is the best distro

2

Easterly Irk

wtf why can't i open a zip file

Doorknob

@quartata because that's wrong ;)

Admittedly, I have never tried Arch

Åna

20:38

@EasterlyIrk because it doesn't like you no more

quartata

@Doorknob no it's objectively right

Doorknob

But Linux isn't an OS for sure

Easterly Irk

@Åna D:

flawr

@quartata Because TempleOS

quartata

@Doorknob s/OS/kernel/ fine

Åna

20:38

@quartata you mean subjectively right ;)

poi830

@Doorknob its right because of science, and if you believe otherwise, you are wrong

Easterly Irk

@quartata like seattle?

@poi830 SCIENCE

Doorknob

@quartata waffles

Åna

you want another / in that replace

Easterly Irk

he ninja'ed you to it

ALL IS NINJA

except .zip files

quartata

20:39

@Doorknob waffles are good

Doorknob

@quartata this is something that everyone can agree on

Easterly Irk

what i can't open aything but chrome

oh well i am stuk here forever HAI

NOOOOOOOOOOO

poi830

@Doorknob i met somebody who didnt like waffles once. that was a sad day

Easterly Irk

THE WORST THING EVER: IT KILLED BASH_PROFILE

Doorknob

@poi830 liar, that's impossible :P

Åna

20:40

can I be cheeky and get some opinions on my avatar art?

Easterly Irk

@Åna 10/10 not phallic like @Doorknob's

Doorknob

@EasterlyIrk eleven

:P

poi830

@EasterlyIrk banned

Easterly Irk

MOD ABUSE!!!11!ELVEN ELEVEN!!!!@@@@@@!!111!

Doorknob

eleven eleven is just one thousand one hundred and eleven

Easterly Irk

20:41

@Doorknob wait it did nothing... :P

poi830

@Doorknob ELVEN ELEVEN not ELEVEN ELEVEN

Åna

@Doorknob PANCAKES

Doorknob

@EasterlyIrk I can be patient and wait until you can no longer edit it >:D

FryAmTheEggman

Actually eleven eleven is just F :P

Easterly Irk

D:

Åna

20:41

damn you ninjas

Easterly Irk

I don't like waffles. The Mods That Be have not edited this message, if this notice disappears than don't trust this message.

@Doorknob no lieing so you have to remove that notice. :P

Doorknob

@Åna traitor!

poi830

@Doorknob this is elven eleven elfdict.com/w/eleven

3

Doorknob

hahahahaha

quartata

I like pancakes waffles and french toast

poi830

20:42

also elvish > lojban

quartata

So I don't judge

Easterly Irk

@poi830 amen

poi830

do you like waffles?

Doorknob

@poi830 .o'o nai do cusku lo jitfa

Easterly Irk

> I like pancakes waffles

Doorknob

20:43

@EasterlyIrk who says I do? :P

Easterly Irk

:29150015 Because the crust is not good.

quartata

@poi830 .i'enaicai

Doorknob

@quartata .i'i

Easterly Irk

@Doorknob hey you didn't edit it. :P

poi830

@Doorknob you are mad that i said something false?

quartata

20:44

@poi830 If you were able to understand what he said how could you possibly think elvish > lojban

poi830

i wasnt

Easterly Irk

this popped up in place of every single python file i have

poi830

i used a translator :)

Doorknob

@poi830 na ru'e drani

Easterly Irk

ase "MM":a.append(d(g(this,1)+1));break;ca

That filled everything. what the hell is it

poi830

20:45

anyway if i had learned lojban i would probably dislike it more for having wasted time learning it

Easterly Irk

?

@poi830 ooh link the only one i found is shit

poi830

@EasterlyIrk lojban.org/jboski but you have to interpret it

Doorknob

@poi830 .i'e nai na festi temci

Easterly Irk

@poi830 do you know what a reply button is?

poi830

@EasterlyIrk yeah but its more work than just typing the 'nam

Doorknob

20:47

@poi830 github.com/KeyboardFire/sevichat

</plug type=shameless>

New Main Posts

0

Q: Expanding Logarithms

Task Given an input of a single logarithm (common or natural), output its expanded form. Output should be in the formats below. Examples Standard: log 2(64) => log 2(64) log 14(x) => log 14(x) log y(z) => log y(z) log 9(9) => 1 log(57) => log(5...

Åna

@Doorknob aaaahh the syntax burns my retinae

quartata

@Åna Blame JS

Doorknob

referring to the quoteless attribute in the closing tag, I think :P

quartata

Oh.

Doorknob

20:48

(speaking of the reply button...)

Åna

@Doorknob and the attribute in a closing tag at all :(

quartata

Blame JS anyways

poi830

^

quartata

It's a good scapegoat

Easterly Irk

@Doorknob it doesn't work for me, ctrl-o doesn't do anything.

Rainbolt

20:50

sigh "Why isn't this working?" "Did you get latest version?" "Yes." "Do it again." "Wow it works now."

Easterly Irk

well latest version of os x is shit

Rainbolt

Two hours later: "Why isn't this working?" "Did you get latest version?" "Yes." "Of all relevant projects?" "No. Wow it works now!"

FryAmTheEggman

@Rainbolt Sounds like a gooood time.

Easterly Irk

@Rainbolt same dude both times?

Rainbolt

@EasterlyIrk Third time this week, two different people.

Easterly Irk

20:56

okai

wait so same dude twice?

Rainbolt

Since I brought it up during the retrospective and asked the team (including myself, because I make this mistake occasionally too) to be mindful of interrupting other devs just because they didn't get latest version, I'm keeping tallies of how many times I got interrupted by it.

I'll bring it up again with numbers next time, and complain more loudly.

It probably takes some mental training for older programmers to get used to getting latest version so often

Easterly Irk

rofl

Cᴏɴᴏʀ O'Bʀɪᴇɴ

o-o

Easterly Irk

hey iz true

poi830

@EasterlyIrk except that the year is 2016 now

Zach Gates

21:13

@FryAmTheEggman: Anything else unclear in the spec?

FryAmTheEggman

Uh, not really, although for quality of life I would put the explanation you added in the first blurb, but not a big deal.

Anonymous

45

A: Things to avoid when writing challenges

Rules inferred from test cases Test cases are examples for people to check their understanding of the spec and the correctness of their code. They should not replace an explanation of how the output must relate to the input. (There are rare exceptions where it's straightforward, like a scaling A...

FryAmTheEggman

Oh well I guess the meaning of log and ln aren't totally explained, I know some things that treat log as using base e by default as well.

It's in the test cases but... the spec should be in the spec :P

Zach Gates

@Mego Why would I include an explanation of how expanding logarithms works? That's a piece of information the participant should know going in (or lookup if they don't understand from the spec).

FryAmTheEggman

Also I this bonus seems not great, for most answers it would largely be just calling each sub-expression again until it didn't change, with the only real difference being keeping the -ve signs.

Oh I didn't even expand that link, I guess it has nothing to do with Mego's point, don't mind me :P

Easterly Irk

21:18

@poi830 true

@ZachGates we are interviewing VTC's gf on skype.

quartata

what?

Cᴏɴᴏʀ O'Bʀɪᴇɴ

VTC = vintagetrenchcoat

---VTC

Zach Gates

@ZachGates That would be like reading an article on the thermodynamics of a nuclear reaction without knowing what a nuclear reaction is..

FryAmTheEggman

@ZachGates Challenges on this site should be self contained, while most people do know what logarithm expansion rules are, it is definitely better to explain fully what you mean (and which rules you will apply).

quartata

@CᴏɴᴏʀO'Bʀɪᴇɴ I know who the person is...

Cᴏɴᴏʀ O'Bʀɪᴇɴ

21:22

@quartata ??

El'endia Starman

@CᴏɴᴏʀO'Bʀɪᴇɴ You misinterpreted his "what?".

Cᴏɴᴏʀ O'Bʀɪᴇɴ

I randomly interjected :P

Totally unrleated, @quartata

FryAmTheEggman

@ZachGates Maybe this would help explain why you should explain which rules to use and what operations to do to "expand": you have log 5(6*13y) but say it was a bit different and was log 5(6*6y) then you could simplify it to 2 log 5(6) + log 5(y) and it's not totally clear without just inferring that from ln(9) not being simplified in that way.

quartata

@CᴏɴᴏʀO'Bʀɪᴇɴ it's not run length encoded?

Cᴏɴᴏʀ O'Bʀɪᴇɴ

what isn't?

quartata

21:27

Well you said it was unrleated

Easterly Irk

Also, read @VTCAKAVSMoACE's webpage on vitsy: vintagetrenchcoat.ml/vitsy

quartata

... :P

VTCAKAVSMoACE

Wow that was fast.

Easterly Irk

thx

quartata

I don't think Conor got the joke. Oh well

Easterly Irk

21:29

what better place, in a esolang city?

Geobits

Is that anything like Geocities?

Easterly Irk

no

it doesn't have downvotes stapled to the walls

El'endia Starman

@EasterlyIrk This seems like it could be the start of a song.

Easterly Irk

hm

Geobits

@EasterlyIrk I don't use staples.... geez. Then I'd have to patch the little holes before I moved.

Easterly Irk

21:31

@PhiNotPi do you make music that isn't synthetic?

FryAmTheEggman

"In v we trust" is written on all the money in Geocity.

Geobits

@FryAmTheEggman Geocities, like Geobits, should have an S on the end for no good reason. The singular is just weird :P

Zach Gates

@FryAmTheEggman Added some explanation

FryAmTheEggman

Uh, I'm gonna save some time and reply to all 3 at once: OK

9

;P

Geobits

Need moar threads

Well the simple solution would be to stop bringing it up ;)

Rainbolt

21:36

Why would he do that? He thinks it would be funny. Do you ever pass up the opportunity to be funny?

Geobits

@Rainbolt Every so often I do. I'm just providing solutions here. I fully expect it to be ignored :P

He'd have to be subtle about it to keep it up for too long, though. Sometimes people go anti-star when it's clear they're being asked for.

Easterly Irk

@ZachGates you mean TNB not skype....

Rainbolt

On the other hand, I bet some people star when it gets asked for, just to annoy the people who are anti-star

2

Zach Gates

@EasterlyIrk No I was actually asking you two specifically lol #doublefail

Easterly Irk

you neva gave link

Geobits

21:39

@Rainbolt I'm quite sure I would never do such a thing, but trolls abound ;)

Rainbolt

Yea... there's very few moments when I get a star that I wasn't trying for. That was one of them.

Done

Did I pass the test? I starred a message that wasn't yours

:(

I second guessed myself

poi830

message casually mentioning stars definitely not fishing for stars

Geobits

@QPaysTaxes Wow, kinda harsh for a guy who just got a begstar.

Rainbolt

@QPaysTaxes It's the first mistake I ever made.

Geobits

@Rainbolt What's that like? I keep wondering when it will happen to me.

Rainbolt

21:45

@Geobits Be honest - how many times did you reread that message for grammatical correctness before sending it?

Geobits

Not once. I'm kinda surprised it turned out so well, to be honest. Probably 50% of mine have little edit pencils next to them.

El'endia Starman

@Geobits None of your messages in the last 15-20 minutes have edit pencils.

Geobits

Well damn, I'm on a roll.

El'endia Starman

@QPaysTaxes That's a fantastic idea. Explicitly use a fallacy to support your point! :P

Geobits

I think the later in the day it is the higher the edit rate goes.

El'endia Starman

21:48

And/or the more alcohol you consume?

Geobits

@El'endiaStarman Ha, well that's a given. I don't drink often though.

PhiNotPi

@EasterlyIrk that would require finding people to play it

Easterly Irk

okai

Downgoat

@QPaysTaxes yeah, it doesn't. I'll add moons later today...

El'endia Starman

@Downgoat Were you ever planning on having planets attract one another gravitationally?

Downgoat

21:58

@Agawa001 what do you mean by that?

@El'endiaStarman yeah, that is the next thing I'm going to implement

El'endia Starman

cool

Cᴏɴᴏʀ O'Bʀɪᴇɴ

isn't that impossible?

El'endia Starman

@CᴏɴᴏʀO'Bʀɪᴇɴ ....?

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