Create array of 24 with odd numbers as null

Question

Here's my code:

var myArray = new Array();
for (var i = 0; i < 24; i++ ){
            myArray.push([i]);
        }

How can I add/replace null values where there's 1, 3, 5, 7, 9...... ?

it should be like: 0, null, 2, null, 4, null, 6, null, 8.......... — alex, Feb 26 '15 at 08:05
Split your issue in little part : first you need a function which tell if a number in parameter is a prime number. Then, use this function to replace by `null` value the prime number and you are done. **Edit** : plus, I quickly took a look at http://www.mathsisfun.com/prime_numbers.html and it seems not to be what you say. Did you mistake with odd and even numbers ? — Anwar, Feb 26 '15 at 08:07

score 2 · Accepted Answer · answered Feb 26 '15 at 08:08

2

Use this

for (var i = 0; i < 24; i++ ){
     if(i%2===1){
          myArray.push(null);
     else{
            myArray.push([i]);
        }
}

answered Feb 26 '15 at 08:08

Vaibhav

1,479
8
13

score 1 · Answer 2 · answered Feb 26 '15 at 08:12

For prime numbers and null:

var arr = [], i, j, primeNum = [];
for (i = 2; i <= 24; ++i) {
    if (!arr[i]) {
        primeNum.push(i);
        for (j = i << 1; j <= 24; j += i) {
            arr[j] = true;
        }
    } else {
        primeNum.push(null);
    }
}
console.log(primeNum)

If you just want the odd numbers as null:

var arr = [];
for (var i = 0; i < 24; i++ ){
    if( i % 2 === 1){
        arr.push(null);
    } else {
        arr.push(i);
    }
}
console.log(arr)

Create array of 24 with odd numbers as null

2 Answers2