How to fill the missing values in an array with another array

Question

How to fill the missing values in the array1

array1 = [1,'',12,23,'',5]

basically, they are 3 values but only 2 values can be placed

array2 = [6,8,9]

sample output

array1 = [1,6,12,23,8,5]
array2 = [9]

Welcome to Stack Overflow! Please take the tour if you haven't already (you get a badge!) and read through the help center, in particular How do I ask a good question? Your best bet here is to do your research, search for related topics on SO and elsewhere, and give it a go. If you get stuck and can't get unstuck after doing more research and searching, post a minimal reproducible example showing your attempt and say specifically where you're stuck. People will be glad to help. — T.J. Crowder
– T.J. Crowder, Commented Mar 24, 2022 at 9:34
Just a side note: Those aren't missing values, they're strings. I mention this because JavaScript arrays can actually have missing values because they can be sparse. You could create that array with actually missing values by doing this: const array1 = []; array1[0] = 1; array1[2] = 12; array[3] = 23; array1[5] = 5; or slightly more obscurely: const array1 = Object.assign([], {0: 1, 2: 12, 3: 23, 5: 5}); — T.J. Crowder
– T.J. Crowder, Commented Mar 24, 2022 at 9:37
@t-j-crowder this is noted. Next time I'll include my attempts in my questions. Thank you so much! — johnv
– johnv, Commented Mar 24, 2022 at 9:43

Trevor Dixon · Accepted Answer · 2022-03-24 09:38:36Z

3

Start with something like this.

array1 = [1,'',12,23,'',5]
array2 = [6,8,9]
array1 = array1.map(val => val === '' ? array2.shift() : val);

Or

for (let i = 0; i < array1.length; i++) {
  if (array1[i] === '') array1[i] = array2.shift();
}

Read about https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/shift. Have fun!

answered Mar 24, 2022 at 9:38

Trevor Dixon

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Michael Han · Accepted Answer · 2022-03-24 09:49:46Z

0

let array1 = [1,'',12,23,'',5]
let array2 = [6,8,9]
for (var i = 0; i < array1.length; i++) {
    if(array1[i]=== ''){
        console.log(array1[i])
         array1[i] = array2.shift()
    }
}

answered Mar 24, 2022 at 9:49

Michael Han

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Mamunur Rashid · Accepted Answer · 2022-03-24 10:02:40Z

0

let array1 = [1,'',12,23,'',5];
const array2 = [6,8,9];

array1 = array1.map((item) => {
    if (Boolean(item)) {
        return item
    } else {
        return array2.shift();
    }
});

console.log(array1);
console.log(array2);

answered Mar 24, 2022 at 10:02

Mamunur Rashid

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