How to convert simple array into two-dimensional array (matrix) with Javascript

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 ins

Answer 1

function matrixify( source, count )
{
    var matrixified = [];
    var tmp;
    // iterate through the source array
    for( var i = 0; i < source.length; i++ )
    {
        // use modulous to make sure you have the correct length.
        if( i % count == 0 )
        {
            // if tmp exists, push it to the return array
            if( tmp && tmp.length ) matrixified.push(tmp);
            // reset the temporary array
            tmp = [];
        }
        // add the current source value to the temp array.
        tmp.push(source[i])
    }
    // return the result
    return matrixified;
}

If you want to actually replace an array's internal values, I believe you can call the following:

source.splice(0, source.length, matrixify(source,3));