Coding Challenge

🥧 Happy Pi Day 2020! In this challenge, I build a simple web application using p5.js and node.js to search in the first billion digits of Pi. Code: thecodingtrain.com/challenges...
🕹️ p5.js Web Editor Sketch: editor.p5js.org/codingtrain/s...
🎥 Previous video: • Coding Challenge #155:...
🎥 Next video: • Coding Challenge #157:...
🎥 All videos: • Coding Challenges
References:
🔗 Pi Searcher: angio.net/pi/
🔗 Peek in Pi: pi.fathom.info/
🔗 Boyer-Moore String Search: en.wikipedia.org/wiki/Boyer%E...
🔗 createReadStream(): nodejs.org/api/fs.html#fscrea...
Videos:
🎥 ES6 Arrow Function: • 16.3: ES6 Arrow Functi...
🎥 Server-side with Node.js: • 2.1 Server-side with N...
🎥 Working with Data and APIs track: • Working with Data and ...
🔴 Coding Train Live 189: • Coding Train Live 189:...
Related Coding Challenges:
🚂 #140 Leibniz Formula for Pi: • Coding Challenge #140:...
🚂 #161 Estimating π from Random Numbers with Euclid's Algorithm: • Coding Challenge 161: ...
🚂 #169 Pi in the Sky Game: • Coding Challenge 169: ...
Timestamps:
0:00 Introduction
2:30 Importing Pi Into p5.js
3:37 Searching Numbers in Pi
7:09 IndexOf Function
13:13 Importing 1GB File
16:38 Dividing the Data into Read Streams
18:25 Searching 1 Billion Digits
19:44 Creating an API
28:42 Conclusions and Ideas
Editing by Mathieu Blanchette
Animations by Jason Heglund
Music from Epidemic Sound
🚂 Website: thecodingtrain.com/
👾 Share Your Creation! thecodingtrain.com/guides/pas...
🚩 Suggest Topics: github.com/CodingTrain/Sugges...
💡 GitHub: github.com/CodingTrain
💬 Discord: thecodingtrain.com/discord
💖 Membership: kzbin.infojoin
🛒 Store: standard.tv/codingtrain
🖋️ Twitter: / thecodingtrain
📸 Instagram: / the.coding.train
🎥 Coding Challenges: • Coding Challenges
🎥 Intro to Programming: • Start learning here!
🔗 p5.js: p5js.org
🔗 p5.js Web Editor: editor.p5js.org/
🔗 Processing: processing.org
📄 Code of Conduct: github.com/CodingTrain/Code-o...
This description was auto-generated. If you see a problem, please open an issue: github.com/CodingTrain/thecod...
#math #piday #nodejs #p5js #javascript

[@dermathze700]

0:40 "A ressource where you can download all the digits of Pi." Wait, ALL of them? That's a very impressive website.

[@speedfastman]

The technology is finally here!

[@MohamedSaad-zy7pu]

pi has infinitely many digits no database ever could hold all digits of pi

[@v0xl]

@@MohamedSaad-zy7pu woosh

[@xnick_uy]

I can give you all the digits of pi right here in this comment: 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9. Just rearrange and repeat some of them as you see fit to recreate pi. You are welcome. :-)

[@Firestar-rm8df]

@@xnick_uy XD

[@lucasschiavetti2799]

Hey. I am just a random 30 yo Brazilian geologist switching carreers and I want to say that today is saturday night, world has corona, I am anxious, alone, thinking about life but this video and your work/passion/humour make things easier for me and I am sure for a lot of other people. Keep up the good work. We appreciate it.

[@sombracep12]

Boa Cara, muita gente de programação é de outras áreas.

[@Kokurorokuko]

28:18 Shocking news! Man found last ten digits of PI

[@luisgeniole369]

We can use the tail command in bash to find the last ten digits of pi like so: tail -c 10 pi-billion.txt

[@kimeg7294]

"last ten digits of KNOWN PI sequence"

[@Cry53r]

@@kimeg7294 Oh... Oh no, sweet child... A billion is just the first sneeze of what has been calculated.

[@ffggddss]

Bigger shock - they turned out to be . . . 9876543210. Fred

[@marcpietro2732]

Who noticed Dan replaced so many times "million" by "billion", by deleting "million" and writing "billion" instead (or vice versa), while there is just one letter to change?

[@TheCodingTrain]

🤦‍♂️

[@elementallobsterx]

No way Dan... ALMOST 1 MILLION SUBSCRIBERS NOW!? I remember your classic P5 tutorials before the whole coding train thing even existed!! I just wanna say, I'm proud, man.

[@TheCodingTrain]

Thank you!

[@0FG0]

I am always a bit amazed at how incredibly much larger a billion is than a million. I know the math is super simple, but the intuition of it is really difficult for me to grasp

[@xot9897]

Morten Flecks if you look at a millimetre on a metre stick, same ratio

[@shreerangvaidya9264]

Look back a dozen decades when the definition of billion was a million million in England, and you will be more amazed.

[@InXLsisDeo]

That's why people don't realize how being a billionaire is completely unnecessary and actually detrimental to society. See it like this: if your salary was 1 million $ per month (not per year, per month), it would take 84 years (aka more than an entire working lifetime) to earn a billion $. And that would be without spending a single $ or paying any tax during all that time.

[@InXLsisDeo]

@@shreerangvaidya9264 no, it's a thousand million. A million million is a trillion.

[@097_shashanksahu6]

Do everyone will ignore the fact that , coding train will soon hit 1 million subscribers. I didn't even how when you reached too close to 1M. It had been 3-4 years now since i am watching your videos.... You taught me processing, you taught me the Nature Of code.... This channel is absolute gold.... I don't remember whats the first video i watched but i could proudly say that i had watched almost every of them. 😍 love from india Dan❤

[@thomasdevelops3087]

shashank Sahu he has hit 1 million as of today!

[@MinisBett]

Finally another Coding Challenge! I really hope for more coding challenges, I really like these videos!

[@thomasdevelops3087]

Congrats on 1 millions subs! Love these challenges! I wish you a lot of luck in the future of your channel

[@LandonHughes2]

Ah!!! You are so close to 1 million subs!! Congrats Dan! You’ll always be the guy that made programming click for me :)

[@Budzique]

Pi was calculated to 50Trillion digits, a text file is available but it's 40TB! Today it's also been added to the pi.delivery api

[@bilallaaroussi7110]

What is the use of this

[@ffggddss]

@@bilallaaroussi7110 Esoteric. It's of some interest to mathematicians to know whether there are any non-random patterns in the digits of π, and these mammoth collections of digits can be used to answer such statistical questions. Fred

[@ffggddss]

50 trillion digits in 40 trillion bytes? Must be slightly compressed, no? (Even if that's the binary terabyte = 2⁴⁰ B, 40 TB ≈ 44.0 trillion bytes.) Fred

[@Xnoob545]

50T 40TB Wot

[@oblivion_2852]

Use it for some good random numbers

[@zaynbaig3157]

Ayyyye our first coding challenge in a while! And a good one at that!

[@jAMES-xy6wh]

You are the best. Your energy is incredible, the world needs more like you. My wife asks what is that song you are singing? lol a man in his 50s singing coding train. THANKS!!!

[@giveaway4002]

waiting for this on pi day!!!!!

[@vishalmishra1937]

this man can visualize anything

[@Jack-cu5il]

Nice! I saw this suggestion on the github and was hoping you'd do it.

[@airxperimentboom]

Love it!

[@dave6012]

The fact that the first million digitals is 1mb and the first billion is 1gb gives me great satisfaction.

[@newzenvigor]

This is my first video. I love this guy already. He makes learning coding fun. 😊

[@Nola1222Piano]

I love this!

[@debumukhopadhay541]

0:00 Why, happy Pi day to you too!

[@RubyPiec]

Cool idea!

[@el_magoxd]

I promise you that I was waiting this video from 1 year ago

[@GrayBlood1331]

That buzz sound effect kept jump scaring me!

[@assenv]

jup the buzzer is just wrong. short conductor whistle or passing train will be much more fitting ;)

[@moussaibrahem9]

the video title should be *Writing Built in Javascript Function* 😂😂 Thanks for this great video

[@jasonspence]

It would be really neat to have the node server lazily evaluate pi as you search, until it finds the string of digits, no matter how long it takes.

[@joostvanrens]

Peek in pi => pecan pie, just so it's easier to remember

[@KellyMurphy]

BCD encoding the file would be 500Meg for a 1 billion digits file, not sure how much you'd get from gz or zip since pi is a high entropy number.

[@NStripleseven]

Can we get some more coding challenges? Maybe 3D tic-tac-toe or adding physics to your fractal trees from ages ago?

[@CEBRAHULKANTWA]

KMP is best algorithm for me.

[@xot9897]

Great video, youre a very engaging teacher, would you consider doing some videos on functional programming, preferably Haskell, I have trouble understanding it and there hardly any good tutorials on KZbin

[@surendrasandun]

I love pi day challange😍

[@axelmoriceau8435]

You know things get handy when it comes to a 1GB file of plain text

[@adamwest8332]

This requires at last 1gb or RAM! Yiou should search directly from the stream, searching in chunk by chunk

[@TheCodingTrain]

Good point!!!

[@Budzique]

I have plenty enough file storage on my local server for 1 trillion digits (43.7GB), I may be able to set it up as a coding challenge by dumping the variables as I run out of ram and searching chunks of the file, but it would be quite a slow process.

[@Xnoob545]

But shouldnt it be 1TB thats insane compression

[@andrewnunes9148]

Try to use KMP algorithm and look for matchs while you read the stream

[@Xiaolong-sh5tl]

I came here for Pie... but all he was talking about was PI.

[@charliedinerman7941]

You should calculate pi in the code so you can just set a number for the number of digits you want

[@basilbaby2069]

Close to 1 million subscribers ♥️♥️

[@hudademirtas3144]

Why You Dont try make a random face ganerator in processing(or you cant do that?)

[@lucaseaston]

If you substituted music notes for numbers, what would Pi sounds like? You could also see if you could find certain melodies within Pi. Edit: I commented this before watching till the end of the video haha.

[@avi12]

10:04 If the condition ends up being true, you can just return -1 instead of keeping track of a variable "found"

[@Justinba1010]

You can't do so, you need to exhaustively search the entire string. Say you're looking for 1419, U would go 1 4 1, then 5, but you cannot exit there.

[@XallbX]

Make a Picross solver.

[@adrianshawuk]

You must do Tau Day too

[@purifierphoenixthemecca2074]

Bailey-Borwein-Plouffe formula

[@haris621]

After 1 billion you would need to use algorithms similar to sorting algorithms.

[@bensmart2829]

He even included inside in the title

[@necaton]

Happy Pi day!

[@DannySullivanMusic]

This certainly has been an interesting year so far...

[@ryan-heath]

You could speed it up by a factor of 4 by instead of search for chars, search for longs (that is 4 chars at once). Caveat is that your search string should be at least 4 chars ... Even faster would be keeping track of where all digits are, that would speed it up by factor of ten, but you would use 10 times more memory. Performance tuning is always a trade-off for something else 😬

[@TheCodingTrain]

Thanks for these suggestions!

[@agcummings11]

The computer would still have to compare the sane number of bits, so it isn’t really a 4x speed up

[@ryan-heath]

See it like this: compare 12 bytes or compare 3 longs. The amount of bits is the same but the CPU can do it in less instructions, thus faster.

[@nonono8108]

Oh, do you have a new character?

[@thomasdevelops3087]

When is 1 trillion coming haha

[@mitchellpincham595]

What about actually calculating the first thousand or million or so digits of pi?

[@farhannr28]

Damm i even still haven't moved on since the last pi day special

[@qwertygmr4521]

Well, here In Spain we write the date in different order, so it is 14/3/20. Which is pretty sad 😞😞

[@leo848]

Qwerty GMR Same in Europe

[@cosminturtureanu692]

@@leo848 Spain is in Europe

[@cosminturtureanu692]

@@HiHi-ur3on oh yeah.. i forgot it just moved

[@cosminturtureanu692]

@@HiHi-ur3on yeah.. after all, you should eat your cereal

[@leo848]

Cosmin Cosmin I meant holy Europe

[@InXLsisDeo]

No need for a bigger file. The natural challenge here is to compute the digits themselves. But I guess it requires a bit of mathematics.

[@SimonTiger]

Code simplification: let start = search.charAt(0); for (let i = 0; i < txt.length; i++) { if (txt.charAt(i) === start) { let found = true; for (let j = 1; j < search.length; j++) { if (txt.charAt(i + j)) !== search.charAt(j) { found = false; break; } } if (found) { return i; } } } return -1; is the same as for (let i = 0; i < txt.length; i++) { if (txt.charAt(i) === search.charAt(0)) { let found = true; for (let j = 1; j < search.length; j++) { if (txt.charAt(i + j)) !== search.charAt(j) { found = false; break; } } if (found) { return i; } } } return -1; is the same as for (let i = 0; i < txt.length; i++) { let found = true; for (let j = 0; j < search.length; j++) { if (txt.charAt(i + j)) !== search.charAt(j) { found = false; break; } } if (found) { return i; } } return -1;

[@angshu7589]

All your videos are so great and so entertaining. Oh and: function askQuestion(question, sender) { if ( typeof question !== "string" && typeof sender !== "string" ) { return "The question and sender is not a proper one"; } if (question == "Any ideas for another video?" && sender == "David Shiffman") { return { getTheIdea: function() { console.log("Put the code to run this console.log as a reply"); } dumpIdea: function() { try { this.getTheIdea = null; } catch (e) { console.error("getTheIdea Cannot be deleted"); } } } } return "Sorry, No answer here..."; }

[@sujatapanigrahy7172]

Im gonna make this in python

[@Jack-yz6yp]

1 mill!!

[@zulnabilfaizmoh.alhadad8729]

Sir, I like how you deliver content about machine learning. I really want good people like you to contribute in the fight against corona virus. I have an idea, what if you create content about the neural network chatbot. I think this is useful for socialization about corona virus to the public. Some doctors say, prevention is the best medicine for all diseases. The socialization of preventing corona virus at this time is the most needed thing to suppress the virus spread. Thanks, i hope you at least read this.

[@BGhoshPikaPikachu]

Happy Gilfoyle

[@flamexode]

How about searching for the digit of a certain digit in pi? Could be an interesting recursive function

[@mikewonghongkee4480]

Happy 🥧 day🤓

[@JurajPecháč]

Game made with p5.js: spaceadvent.glitch.me/

[@prabhatkumar8173]

Hi can make programe which can read the chart provided by a website on the screen and create signals on activity detected !?

[@hakankosebas2085]

Make plastic deformation simulation

[@JambaYCS]

i was in chat during the stream :))

[@delta619]

what if i +j will exceed the length of the text file , when the value of i is at last , or somewhere in the last

[@luisgeniole369]

27:56 We can use the tail command in bash to cat the last ten digits like so: tail -c 10 pi-billion.txt

[@delta619]

Brent Trenholme i thought it may give an exception something like out of bounds.

[@delta619]

Brent Trenholme yeah 😄, thnx

[@TheCodingTrain]

indeed, i should have accounted for this!

[@delta619]

The Coding Train i need coding train sticker for my laptop if i may ask. 🥺 Fan from India

[@silentgrove7670]

Is there a pi inside pi find 3 then 31 then 314 then 3141 I wonder what that sequence would look like ?

[@techsupport3227]

Do you know any other code languages other than java script? I learned the bare minimum of java script and now I’m learning html to create a website for my friend

[@leo848]

I forgot it was pi day... SHAME ON ME

[@levinsondsouza]

you are pi pi poo poo

[@RubyPiec]

@@levinsondsouza pie pie?

[@davidcullingford5708]

double value=sqrt(2.0); println(value); // prints many decimal places. text(value, 100,100); gets an error.

[@danielzaiser]

what the hell dude, why you gotta do me like that? At 0:59 your buzzer sounds exactly like my door bell and i went outside to check if anybody just rang... *EDIT:* and he keeps using that buzzing sound throughout the video....

[@TheCodingTrain]

Ooops, sorry about that!

[@John-qx1xn]

Or, in two minutes but with no error checking but including time to download file: import sys target = sys.argv[1] data = open('onemeg.dat').read() pos = data.find(target) if pos < 0: print '{} not found'.format(target) else: print '{}: {} {}'.format(pos, target, data[pos+len(target):pos+41])

[@chadwickhjones]

Pi day should be 14% through the month of March, not the 14th day of March.

[@iradnuriel9087]

You could implement kmp algorithm, this algorithm is not so hard to implement...

[@Julian-xe5is]

wasn't pi supposed to be a non-repeating and non-terminating decimal number? there are repeating numbers in this video though (such as ....99999....)?

[@thenormalguy8574]

hey dan! i am trying to implement this to my express server which holds projects, but it seems like the app.use overrides the front page (which is "/"). can anyone help me?

[@xxxxxijhin]

NINE NINE NINE NINE NINE NINE

[@bencekovacs8726]

You are supposed to use pattern matching for this problem, and not for loops..

[@lucasg.5534]

you are supposed to shut up

[@sirynka]

Isn't it as easy as pressing ctrl+f inside a pi.txt file?

[@CyCloNeReactorCore]

What program is he using?

[@SquooshyShark1000]

15:07 it's not binary, it's hexadecimal I know that because I do Unicode stuff every now and then

[@Justinba1010]

They're interchangeable in this context. It is just outputted as hexadecimal, it is technically a binary, usually buffers are binary data. What does unicode have to do with this anyway?

[@dekanex]

Why number 3 is not in?

[@milothegoat280]

9:40 is he writing on the wall with a sharpie??

[@TheCodingTrain]

don't worry it's a dry erase whiteboard

[@olasoderlind5685]

is there a Prossesing Server ?

[@zfoell]

Suggestion for the editor: have music playing in the background and increase the volume of the music when showing a fast forwarded lapse of Dan working through code, rather than having the music cut in and out

[@ZK-im6er]

Is it maybe fun, to find self indexing numbers in the first billion numbers of Pi? So like 3.1415(edit) 1 would be index 1 and thus be its own index. Or maybe if 1 would index 0. I got the idea from this Numberphile video about looping numbers in Pi( starting with a given number, finding its index, than looking at that numbers it index and so on) Here is the video kzbin.info/www/bejne/jWOTkodnadlrhtk

[@origedit]

Peeing inside Pik -_-

[@shurmurray]

But 1 million digits of Pi file should weight only about 2 megs - in 2020 it is nothing even for JS. It is very small amount of memory. And, well, 1 billion is about 2 gigs, depends on encoding.

[@jakobus5098]

grep

[@manuelesparza5321]

dude literally i had this idea like a week ago to publish it today (pieandme.com)

[@pascha4527]

10:00 txt.charAt(int) at line 17 could overflow.....

[@Xnoob545]

Do 1 trillion

[@wt030]

Great video, but this annoing sound when you correct yourself...

[@flolow.4990]

Here is the code for Processing(Java): String raw[]; String digits; String surch = ""; void preload() { raw = loadStrings("pi.txt"); } void setup() { size(500, 500); preload(); digits = raw[0]; } void draw() { background(0); suchBox(); int index = digits.indexOf(surch); fill(0, 100, 255); text(index - 1, width/2, height/1.5); } void keyPressed() { if (keyCode == BACKSPACE) { surch = ""; } else { surch += key; } } void suchBox() { rectMode(CENTER); textAlign(CENTER, CENTER); fill(255); stroke(0); rect(width/2, height/2, width/2, height/8); fill(0); textSize(20); text(surch, width/2, height/2); }

[@grainfrizz]

This is O(N²)

[@amey7064]

It's actually pretty close to theta(n), since the length of the sequence to be searched is small relative to s billion digits

[@ryan-heath]

I think the big o is still O(N) It would be O(N^2) when your search string would be always as big as the digits of PI

[@ebentee]

Whoever read this, you'll be successful one day. Let's do this for the future

[@andrewqi6695]

7th

[@lukasjetu9776]

Pie.