$dll = new SplDoublyLinkedList();
$dll->push(2);
$dll->push(3);
$dll->unshift(5); // add 5 beginning of the array
$dll->rewind();
while($dll->valid()){
    echo $dll->current()."\n";
    $dll->next();
}
Output 
5
2
3(PHP 5 >= 5.3.0, PHP 7, PHP 8)
SplDoublyLinkedList::unshift — Prepends the doubly linked list with an element
   Prepends value at the beginning of the doubly linked list.
  
valueThe value to unshift.
Не повертає значень.
$dll = new SplDoublyLinkedList();
$dll->push(2);
$dll->push(3);
$dll->unshift(5); // add 5 beginning of the array
$dll->rewind();
while($dll->valid()){
    echo $dll->current()."\n";
    $dll->next();
}
Output 
5
2
3