How to split a big number into individual digits in Javascript?

Question

I'm currently working my way through the Euler project, and currently I need to split a 1000 digit number into an array.

I've tried this :

var number = big number here;
var digits = number.toString().split('');

It works fine for small numbers, but as soon as the input gets big enough the array will be on scientific notation, e.g. :

[ '1', '2', '3', '1', '2', '4', 'e', '+', '2', '2' ]

Is there a way around this?

Thanks in advance!

EDIT: Needed for problem 8 on Euler Project (https://projecteuler.net/problem=8)

You can't directly represent a 1000-digit number in JavaScript. Which Project Euler question is it? — Pointy, Jun 25 '16 at 15:54
why don't you copy it as a string? Just copy it as a string and then `split('')`. — Gerardo Furtado, Jun 25 '16 at 15:56
I guess I will just split it several times in an array of size 13. — JalxP, Jun 25 '16 at 15:56
Have you checked this? http://stackoverflow.com/a/1685917/1702612 — Bikas, Jun 25 '16 at 15:58
Put it in a string. Don't bother to make it an array since you can use subscript functions just as easily. Be aware of http://stackoverflow.com/questions/5943726/string-charatx-or-stringx — Nathaniel Johnson, Jun 25 '16 at 16:05
You don't need to represent the "number" as a number however; you can just treat it as an array of digits. — Pointy, Jun 25 '16 at 16:06
I don't want to spoil your exploration but do consider the likely range of the solution to multiply 13 digits. — Nathaniel Johnson, Jun 25 '16 at 16:08
There is no need to split a string. Indexes work fine on strings. `var a = '123456'; var b = a[0] * a[1] * a[2];` — Alex Kudryashev, Jun 25 '16 at 17:17
Thanks everyone, I've solved it working with a string instead. Thanks for all references! — JalxP, Jun 28 '16 at 10:44

score 0 · Answer 1 · answered Jun 25 '16 at 16:34

number = "7316717653133062491922511967442657474235534919493496983520312774506326239578318016984801869478851843858615607891129494954595017379583319528532088055111254069874715852386305071569329096329522744304355766896648950445244523161731856403098711121722383113622298934233803081353362766142828064444866452387493035890729629049156044077239071381051585930796086670172427121883998797908792274921901699720888093776657273330010533678812202354218097512545405947522435258490771167055601360483958644670632441572215539753697817977846174064955149290862569321978468622482839722413756570560574902614079729686524145351004748216637048440319989000889524345065854122758866688116427171479924442928230863465674813919123162824586178664583591245665294765456828489128831426076900422421902267105562632111110937054421750694165896040807198403850962455444362981230987879927244284909188845801561660979191338754992005240636899125607176060588611646710940507754100225698315520005593572972571636269561882670428252483600823257530420752963450";
number = number.split('');

greatestvalue=0;
for(i=0; i<number.length; i=i+1){
 value = [parseInt(number[i],10),parseInt(number[i+1],10),parseInt(number[i+2],10),parseInt(number[i+3],10),parseInt(number[i+4],10),parseInt(number[i+5],10),parseInt(number[i+6],10),parseInt(number[i+7],10),parseInt(number[i+8],10),parseInt(number[i+9],10),parseInt(number[i+10],10),parseInt(number[i+11],10),parseInt(number[i+12],10)].reduce(function(previousValue, currentValue, currentIndex, array) {
   return previousValue * currentValue;
 });
 if(value>greatestvalue){
  greatestvalue=value;finalindex=i;
 }
}

i = finalindex;
greatestnumbers = [number[i],number[i+1],number[i+2],number[i+3],number[i+4],number[i+5],number[i+6],number[i+7],number[i+8],number[i+9],number[i+10],number[i+11],number[i+12]];
document.write("Greatest Value: "+greatestvalue +"</br>Final Index: "+finalindex+"</br>Greatest Numbers: " + greatestnumbers);

score 0 · Answer 2 · answered Jun 25 '16 at 16:49

If you just want to use a String rather than Array to appoximate the value :

var chaine = nombre.toString();
console.log(chaine);
index = chaine.indexOf("+");
if (index != -1){
  var exposant = chaine.slice(index+1);
  var mantisse = chaine.slice(0, index-1);
  var longueur = mantisse.slice(mantisse.indexOf(".") + 1).length;
  var body = mantisse.substr(0, 1).concat(mantisse.slice(mantisse.indexOf(".")+1));
  var digit = body.concat("0".repeat(exposant-longueur));
  console.log(digit);
}

How to split a big number into individual digits in Javascript?

2 Answers2