访问模型没有foreach

If its possible to access the 'entry_id' data in a foreach loop as below, if I know there is only one item, is there a better way to access it?

$arr = array();

foreach( $order->items as $item ) {
    $arr[] = $item->entry_id;
}

If order->items is no-associative array and its only 1 element, you can access it this way:

echo $order->items[0]->entry_id;

But more safe will be check how many items in array:

if(count($order->items) > 0)
    echo $order->items[0]->entry_id;