//isEmpty 是 SplDoublyLinkedList 的一個方法
$obj = new SplDoublyLinkedList();
// 檢查鏈結串列是否為空
if ($obj->isEmpty())
{
$obj->push(2);
$obj->unshift(10);
}
print_r($obj);
//輸出如下
SplDoublyLinkedList 物件
(
[flags:SplDoublyLinkedList:private] => 0
[dllist:SplDoublyLinkedList:private] => 陣列
(
[0] => 10
[1] => 2
)
)