JavaScript: How to Get the Values from a Multi-Dimensional Array?

Question

I'm trying to get the values from a multi-dimensional array. This is what I have so far.
I need the value of 99 and the image when I select the first option in the array, e.g. "Billy Joel".

var concertArray = [
 ["Billy Joel", "99", "equal.png"],
 ["Bryan Adams", "89", "higher.png"],
 ["Brian Adams", "25", "lower.png"]
];
function populate(){
 for(i = 0; i < concertArray.length; i++){
 var select = document.getElementById("test");
 select.options[select.options.length] = new Option(concertArray[i][0], concertArray[i][1]);
 }
}

Answer 1

You can try to transform the multi-dimensional array to an array of objects like this:

var concertArray = [
 {name: "Billy Joel", value: 99, image: "equal.png"},
 {name: "Bryan Adams", value: 89, image: "higher.png"},
 {name: "Brian Adams", value: 25, image: "lower.png"}
];

Then you can access the items in the array like regular objects:

var concertName = concertArray[0].name;
var concertPrice = parseFloat(concertArray[0].value);
var concertImage = concertArray[0].image;

• aspiring: How to iterate this kind of an array?

Answer 2

let concertArray = [
 ["Billy Joel", "99", "equal.png"],
 ["Bryan Adams", "89", "higher.png"],
 ["Brian Adams", "25", "lower.png"]
];
let i = 0;
console.log(concertArray[i][1]) // 99
console.log(concertArray[i][2]) // equal.png

• kentrenholm: Thanks so much.... Now, what would I have to do to complete the concertImage in this structure: concertName = concertList.options[concertIndex].text; concertPrice = parseFloat(concertList.options[concertIndex].value); concertImage = ???

Answer 3

AFAIK, the Option constructor only takes two arguments, the text and the value. If you want to pass more data, I suggest you use the HTML5 data API:

var opt = new Option(concertArray[i][0], concertArray[i][1]);
opt.setAttribute('data-image', concertArray[i][2]);
select.options[select.options.length] = opt;

Then you can grab it using getAttribute('data-image')

Answer 4

You can access values by using 2 for loops as below.

var concertArray = [
 ["Billy Joel", "99", "equal.png"],
 ["Bryan Adams", "89", "higher.png"],
 ["Brian Adams", "25", "lower.png"]
 ];
function populate(){
 for(i=0;i<arr.length;i++)
 {
 for(j=0;j<arr[i].length;j++)
 {
 console.log(arr[i][j]);
 }
 }
}

• Kir Mazur: This answer is awfully bad for large arrays.