JSON - 使用PHP的push_array

Question

can someone please explain to me why the first one is working and the second one not? The result is in the second example simply "1".

1.

    $c = 0;
    $list = array();
    foreach ($places as $place) {
        $arr = array();
        $arr[0] = get_object_vars($place);
        $list[$c] = $arr;
        $c++;
    }
    echo json_encode(array("status" => "true", "list" => $list));

2.

    $list = array();
    foreach ($places as $place) {
        array_push($list, get_object_vars($place));
    }
    echo json_encode(array("status" => "true", "list" => $list));

Sample data for both code samples:

$places = array();

$place = new StdClass;
$place->name = 'first';
$place->location = array('x' => 0.0, 'y' => 0.0);
$places[] = $place;

$place = new StdClass;
$place->name = 'Greenwich Observatory';
$place->location = array('x' => 51.4778, 'y' => 0.0017);
$place->elevation = '65.79m';
$places[] = $place;

Answer 1

In the first case you are adding a key value pair to the array, in the second case just the value. I believe just adding the value SHOULD in fact work, but maybe

foreach ($places as $place) {
    array_push($list, array( 0 => get_object_vars($place) );
}

will work better?