PHP SplDoublyLinkedList offsetUnset() Function

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The SplDoublyLinkedList::offsetUnset() function is an inbuilt function in PHP which is used to unset the value at given index.

Syntax:

void SplDoublyLinkedList::offsetUnset( $index )

Parameters: This function accepts a single parameter $index which holds the index value whose value to be unset.

Return Value: It does not return any value.

Below programs illustrate the SplDoublyLinkedList::offsetUnset() function in PHP:

Program 1:

<?php  
  
// Declare an empty SplDoublyLinkedList 
$list = new \SplDoublyLinkedList; 
  
// Use SplDoublyLinkedList::add() function to  
// add elements to the SplDoublyLinkedList 
$list->add(0, 30); 
$list->add(1, 20); 
$list->add(2, 30); 
$list->add(3, "Geeks"); 
$list->add(4, 'G'); 
$list->rewind(); 
  
// Use SplDoublyLinkedList::offsetUnset() function 
// to unset the value at given index 
$list->offsetUnset(0); 
  
$list->offsetUnset(1); 
  
$list->offsetUnset(0); 
  
$list->offsetUnset(1); 
  
var_dump($list); 
  
?>  

Output:

object(SplDoublyLinkedList)#1 (2) {
  ["flags":"SplDoublyLinkedList":private]=>
  int(0)
  ["dllist":"SplDoublyLinkedList":private]=>
  array(1) {
    [0]=>
    string(5) "Geeks"
  }
}

Program 2:

<?php  
  
// Declare an empty SplDoublyLinkedList 
$list = new \SplDoublyLinkedList(); 
  
// Use SplDoublyLinkedList::push() function to  
// add elements to the SplDoublyLinkedList 
$list->push(1); 
$list->push(2); 
$list->push(3); 
$list->push(8); 
$list->push(5); 
  
// Use SplDoublyLinkedList::offsetUnset() function 
// to unset the value at given index 
$list->offsetUnset(1); 
  
$list->offsetUnset(2); 
  
print_r($list); 
  
?>  

Output:

SplDoublyLinkedList Object
(
    [flags:SplDoublyLinkedList:private] => 0
    [dllist:SplDoublyLinkedList:private] => Array
        (
            [0] => 1
            [1] => 3
            [2] => 5
        )

)

Reference: https://www.php.net/manual/en/spldoublylinkedlist.offsetunset.php