replace some numbers in array

Question

Hi i recently did a number generator and i have an array filled with 0, 0, 0, 0, 0, because it generates numbers from 0 - 99999 and i want to make it replace only a few elements, for example if it generates 123 then i want an array to be [0, 0, 1, 2, 3], if 4467 then [0, 4, 4, 6, 7] etc any suggestions? thats the code i have for array:

let randInt = Math.floor(Math.random() * 100000);
let separated = [0, 0, 0, 0, 0];

separated = Array.from(String(randInt), Number);

For the mathematical way division / and modulo % will help. The other possibility is to use randInt.toString().split("") and then add the missing zeros at the beginning of the array — derpirscher
– derpirscher, Commented Oct 4, 2022 at 13:52

Jaromanda X · Accepted Answer · 2022-10-04 14:15:48Z

3

Here's how you do it

convert the number to a string
pad the string with leading "0" so it is 5 characters long
split
map to Number
profit

OK, the last step is optional :D

// set to 123 to demonstrate
const randInt = 123;// Math.floor(Math.random() * 100000);
const separated = randInt.toString().padStart(5, 0).split('').map(Number);
console.log('Output:', separated);

Another alternative

add 100000 to the random number, therefore you get numbers 100000-199999
toString
split('')
slice(1) (to remove the leading 1)
map to Number

note: the split('').slice(1) can also be slice(1).split('')

So really, that's two more solutions :p

const randInt = Math.floor(Math.random() * 100000 + 100000);
const separated = randInt.toString().split('').slice(1).map(Number);
console.log(randInt, separated);

edited Oct 4, 2022 at 14:15

answered Oct 4, 2022 at 14:01

Jaromanda X

57.1k6 gold badges82 silver badges96 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

epascarello · Accepted Answer · 2022-10-04 14:06:14Z

2

If you want to use a full string, you can use padStart to add in leading zeros. You can split it and map it to the new array.

const separated = Math.floor(Math.random() * 100000).toString().padStart(5, '0').split('').map(Number);

console.log(separated);

You can also just do it from Array.from

const nums = Array.from( {length: 5}, () => Math.floor(Math.random()*10));

console.log(nums);

answered Oct 4, 2022 at 14:06

epascarello

208k20 gold badges206 silver badges246 bronze badges

Comments

Peleg Haham · Accepted Answer · 2022-10-04 14:14:46Z

1

Hope it'll be helpful.

 const randomNum = Math.floor(Math.random() * 100000); 
 console.log('randomNum is ' + randomNum);
 let finalResult = [0,0,0,0,0];
    let result = randomNum.toString().split('');
    result = result.map(num=>parseInt(num));
    const gap = finalResult.length - result.length; 
    if(gap>0){
      for(let i = 0; i< finalResult.length - gap; i++){
        finalResult[i+gap] = result[i];
      }
    }
    else
      finalResult = result;
    console.log(finalResult);

edited Oct 4, 2022 at 14:14

answered Oct 4, 2022 at 13:58

Peleg Haham

1015 bronze badges

4 Comments

Jaromanda X Over a year ago

so, 4 digit numbers up to 9998, instead of 5 up to 99999 ... and still no leading zeros

derpirscher Over a year ago

this produces ['9'] instead of ['0', '0', '0', '0', '9'] if randomNum === 9

Jaromanda X Over a year ago

@derpirscher - it only ever produces 4 digits anyway

benbotto Over a year ago

Math.random is inclusive, exclusive, so it should be Math.random() * 100000. Some of your lets should be consts (randomNum; gap).

Greg Brodzik · Accepted Answer · 2022-10-04 14:36:08Z

0

Leveraging lodash utility padStart and includes logic for variable size max:

import { padStart } from 'lodash';

const MAX = 1000;

let randInt = Math.floor(Math.random() * MAX);
const padTo = MAX.toString().length - 1

const paddedNumArr = (padStart(randInt.toString(), padTo, '0'))
      .split('')
      .map(i => parseInt(i));

edited Oct 4, 2022 at 14:36

answered Oct 4, 2022 at 14:21

Greg Brodzik

1,81710 silver badges9 bronze badges

Collectives™ on Stack Overflow

replace some numbers in array

4 Answers 4

Comments

Comments

4 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

Comments

Comments

4 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related