Question

I try to create a dynamic 2 dimensional array using the prototype.slice.call. The array dimension varies depending on the value k inserted by the user. The code is as follows:

var A = new Array(k);

                if (k > 1) {
                    var args = Array.prototype.slice.call(k, 1);
                    for (var n = 0; n < k; n++) {
                        A[n] = new Array.apply(this, args);
                    }
                }



                alert (A);  

Answer 1

.slice() is the wrong tool. It’s used for making a shallow clone of another Array, or part of the Array.

If you’re looking for a square structure, you’d just use 2 nested loops to create the outer and inner arrays.

var k = 10;

var a = [];
for (var i = 0; i < k; i++) {
    a[i] = [];
    for (var j = 0; j < k; j++) {
        a[i][j] = i + ':' + j;
    }
}

http://jsfiddle.net/zGhnv/

>[["0:0","0:1","0:2","0:3","0:4","0:5","0:6","0:7","0:8","0:9"],
["1:0","1:1","1:2","1:3","1:4","1:5","1:6","1:7","1:8","1:9"],
["2:0","2:1","2:2","2:3","2:4","2:5","2:6","2:7","2:8","2:9"],
["3:0","3:1","3:2","3:3","3:4","3:5","3:6","3:7","3:8","3:9"],
["4:0","4:1","4:2","4:3","4:4","4:5","4:6","4:7","4:8","4:9"],
["5:0","5:1","5:2","5:3","5:4","5:5","5:6","5:7","5:8","5:9"],
["6:0","6:1","6:2","6:3","6:4","6:5","6:6","6:7","6:8","6:9"],
["7:0","7:1","7:2","7:3","7:4","7:5","7:6","7:7","7:8","7:9"],
["8:0","8:1","8:2","8:3","8:4","8:5","8:6","8:7","8:8","8:9"],
["9:0","9:1","9:2","9:3","9:4","9:5","9:6","9:7","9:8","9:9"]]

Notice that I really don’t need to declare the initial length of the Array. I can just add members to each array as needed.

If you want to declare the length up front, you could replace both [] with new Array(k).