[php] json_encode sparse PHP array as JSON array, not JSON object

Array in JSON are indexed array only, so the structure you're trying to get is not valid Json/Javascript.

PHP Associatives array are objects in JSON, so unless you don't need the index, you can't do such conversions.

If you want to get such structure you can do:

$indexedOnly = array();

foreach ($associative as $row) {
    $indexedOnly[] = array_values($row);
}

json_encode($indexedOnly);

Will returns something like:

[
     [0, "name1", "n1"],
     [1, "name2", "n2"],
]