I have an array which prints like this
Array ( [0] => 1691864 [1] => 7944458 [2] => 9274078 [3] => 1062072 [4] => 8625335 [5] => 8255371 [6
This is defined behaviour. The array you show is a non-associative, normally indexed array. Its indexes are implicitly numeric.
If you decode the array in PHP or JavaScript, you will be able to access the elements using the index:
$temp_array = json_decode($temp_json);
echo $temp_array[2]; // 9274078