javascript - Convert simple array into two-dimensional array (matrix)

Question

Imagine I have an array:

A = Array(1, 2, 3, 4, 5, 6, 7, 8, 9);

And I want it to convert into 2-dimensional array (matrix of N x M), for instance like this:

A = Array(Array(1, 2, 3), Array(4, 5, 6), Array(7, 8, 9));

Note, that rows and columns of the matrix is changeable.

Answer 1

Something like this?

function listToMatrix(list, elementsPerSubArray) {
    var matrix = [], i, k;

    for (i = 0, k = -1; i < list.length; i++) {
        if (i % elementsPerSubArray === 0) {
            k++;
            matrix[k] = [];
        }

        matrix[k].push(list[i]);
    }

    return matrix;
}

Usage:

var matrix = listToMatrix([1, 2, 3, 4, 4, 5, 6, 7, 8, 9], 3);
// result: [[1, 2, 3], [4, 5, 6], [7, 8, 9]]