I have an array im trying to loop through to create a new type of array specific to my current page.

My array looks like this:

  //$_SESSION['data'] =
 Array ( [0] => 1 [1] => 0 [2] => Tom [8] => 1 [4] => 1 [5] => 
  Array ( [7] => Array ( [0] => Andrew [1] => 1 [2] => 1 [4] => 0 [5] => avatar.jpg [6] => 1 ) ) [6] =>
 Array ( [0] => 1 [1] => 2 ) )

So in my JS file i have this:

var stats = <? echo $_SESSION['data'][5]); ?> ; //this is the array 

my_data = new Array();
for(var key in stats){

    if(key in my_data){} else { //prevent double entry

    my_data[key] = new Array();
    my_data[key][0] = stats[key][6]; 
    my_data[key][1] = stats[key][5];
    my_data[key][2] = stats[key][2]; 
    my_data[key][3] = stats[key][0];
    }
}

console.log(my_data);

Now in console.log i get this :

[undefined × 7, Array[4]
 0: "1"
 1: "avatar.jpg"
 2: "1"
 3: "Andrew"
 length: 4
 __proto__: Array[0]
 ]

I'm wondering why it is saying undefined x7?