When unsetting an offset, the element will be removed from the double linked list. So the following code:<?php$obj = new SplDoublyLinkedList();$obj->push(4);$obj->push(5);$obj->push(6);$obj->offsetUnset(1);echo "Our Linked List:";print_r($obj);?>Will output:Our Linked List:SplDoublyLinkedList Object( [flags:SplDoublyLinkedList:private] => 0 [dllist:SplDoublyLinkedList:private] => Array ( [0] => 4 [1] => 5 [2] => 6 ))Our New Linked List:SplDoublyLinkedList Object( [flags:SplDoublyLinkedList:private] => 0 [dllist:SplDoublyLinkedList:private] => Array ( [0] => 4 [1] => 6 )Notice that the element with the index 2 has now the index 1. The original element with index 1 did not only had it's value unset but was also removed from the list.