Question

I have the following array…

var arr = [1,2,3,4,5,6,7,8,9] 

I need to convert it to the following…

var newArr = [
    [1,4,7],
    [2,5,8],
    [3,6,9],
];

Is this even possible?

Answer 1

Sure it’s possible; something like this should work.

function manipulate(array, amount) {
    // The array to return
    var ret = [];

    // Add the first few values to the array
    // ret = [[1],[2],[3]];
    for (var i=0;i<amount;i++) {
        ret.push([array.shift()]);
    }

    // Now push the last few values on there.
    for (var i=0;array.length;i = ++i % amount) {
        ret[i].push(array.shift());
    }

    return ret;
}

and then call it like;

manipulate(arr, 3);