How do I separate an integer into separate digits in an array in JavaScript?

Question

This is my code so far:

var n = 123456789;
var d = n.toString().length;
var digits = [];
var squaredDigits = [];
for (i = d; i >= 1; i--) {
    var j = k / 10;
    var r = (n % k / j) - 0.5;
    var k = Math.pow(10, i);
    var result = r.toFixed(); 
    digits.push(result);
}

console.log(digits);

But when I run my code I get this: [9, 1, 2, 3, 4, 5, 6, 7, 8]

If anyone can see the problem or find a better solution I would very much appreciate it!

Answer 1

Why not just do this?

var n =  123456789;
var digits = (""+n).split("");

Answer 2

(123456789).toString(10).split("")

^^ this will return an array of strings

(123456789).toString(10).split("").map(function(t){return parseInt(t)})

^^ this will return an array of ints

Answer 3

What about:

const n = 123456;
Array.from(n.toString()).map(Number);
// [1, 2, 3, 4, 5, 6]

Answer 4

I realize this was asked several months ago, but I have an addition to samccone's answer which is more succinct but I don't have the rep to add as a comment!

Instead of:

(123456789).toString(10).split("").map(function(t){return parseInt(t)})

Consider:

(123456789).toString(10).split("").map(Number)

Answer 5

Modified the above answer a little bit. We don't really have to call the 'map' method explicitly, because it is already built-in into the 'Array.from' as a second argument. As of MDN.

Array.from(arrayLike[, mapFn[, thisArg]])

let num = 1234;
let arr = Array.from(String(num), Number);
console.log(arr); // [1, 2, 3, 4]

Answer 6

const toIntArray = (n) => ([...n + ""].map(v => +v))

Answer 7

Here's an alternative to Nicolás Fantone's answer. You could argue it's maybe a little less readable. The emphasis is that Array.from() can take an optional map function as a parameter. There are some performance gains this way since no intermediate array gets created.

const n = 123456;
Array.from(n.toString(), (val) => Number(val)); // [1, 2, 3, 4, 5, 6]

Answer 8

Move:

var k = Math.pow(10, i);

above

var j = k / 10;

Answer 9

var num = 123456789;
num = num.toString(); //'123456789'
var digits = num.split(""); //[ '1', '2', '3', '4', '5', '6', '7', '8', '9' ]

Answer 10

It's been a 5+ years for this question but heay always welcome to the efficient ways of coding/scripting.

var n = 123456789;
var arrayN = (`${n}`).split("").map(e => parseInt(e))

Answer 11

Another method here. Since number in Javascript is not splittable by default, you need to convert the number into a string first.

var n = 123;
n.toString().split('').map(Number);

Answer 12

I ended up solving it as follows:

const n = 123456789;
let toIntArray = (n) => ([...n + ""].map(Number));
console.log(toIntArray(n));

Answer 13

It's very simple, first convert the number to string using the toString() method in JavaScript and then use split() method to convert the string to an array of individual characters.

For example, the number is num, then

const numberDigits = num.toString().split('');

Answer 14

This will work for a number greater than 0. You don't need to convert the number into string:

function convertNumberToDigitArray(number) {
    const arr = [];
    while (number > 0) {
        let lastDigit = number % 10;
        arr.push(lastDigit);
        number = Math.floor(number / 10);
    }
    return arr;
}

Answer 15

const number = 1435;
number.toString().split('').map(el=>parseInt(el));

Answer 16

let input = 12345664
const output = []
while (input !== 0) {
  const roundedInput = Math.floor(input / 10)
  output.push(input - roundedInput * 10)
  input = roundedInput
}
console.log(output)

Answer 17

It is pretty short using Array destructuring and String templates:

const n = 12345678;
const digits = [...`${n}`];
console.log(digits);

Answer 18

You can get a list of string from your number, by converting it to a string, and then splitting it with an empty string. The result will be an array of strings, each containing a digit:

const num = 124124124
const strArr = `${num}`.split("")

OR to build on this, map each string digit and convert them to a Number:

const intArr = `${num}`.split("").map(x => Number(x))

Answer 19

const toIntArray = (n) => ([...n + ""].map(v => +v))