How can I create a two dimensional array in JavaScript?

How can I create a two dimensional array in JavaScript?

I have been reading online and some places say it isn’t possible, some say it is and then give an example and others refute the example, etc.

How do I declare a 2 dimensional array in JavaScript? (assuming it’s possible)
How would I access its members? (myArray[0][1] or myArray[0,1]?)

Solutions/Answers:

Solution 1:

var items = [
  [1, 2],
  [3, 4],
  [5, 6]
];
console.log(items[0][0]); // 1
console.log(items);

Solution 2:

You simply make each item within the array an array.

var x = new Array(10);

for (var i = 0; i < x.length; i++) {
  x[i] = new Array(3);
}

console.log(x);

Solution 3:

Similar to activa’s answer, here’s a function to create an n-dimensional array:

function createArray(length) {
    var arr = new Array(length || 0),
        i = length;

    if (arguments.length > 1) {
        var args = Array.prototype.slice.call(arguments, 1);
        while(i--) arr[length-1 - i] = createArray.apply(this, args);
    }

    return arr;
}

createArray();     // [] or new Array()

createArray(2);    // new Array(2)

createArray(3, 2); // [new Array(2),
                   //  new Array(2),
                   //  new Array(2)]

Solution 4:

Javascript only has 1-dimensional arrays, but you can build arrays of arrays, as others pointed out.

The following function can be used to construct a 2-d array of fixed dimensions:

function Create2DArray(rows) {
  var arr = [];

  for (var i=0;i<rows;i++) {
     arr[i] = [];
  }

  return arr;
}

The number of columns is not really important, because it is not required to specify the size of an array before using it.

Then you can just call:

var arr = Create2DArray(100);

arr[50][2] = 5;
arr[70][5] = 7454;
// ...

Solution 5:

The easiest way:

var myArray = [[]];

Solution 6:

The reason some say that it isn’t possible is because a two dimensional array is really just an array of arrays. The other comments here provide perfectly valid methods of creating two dimensional arrays in JavaScript, but the purest point of view would be that you have a one dimensional array of objects, each of those objects would be a one dimensional array consisting of two elements.

So, that’s the cause of the conflicting view points.