PHP SplDoublyLinkedList::offsetUnset() Method: Usage and Examples

Deletes the entry at a numeric offset and closes the gap.

The examples focus on the operation itself, including the important distinction: pop removes the end; shift removes the beginning.

What It Does

Use the examples below to observe the behavior on a small dataset before extending it to application code.

Syntax and Return Value

SplDoublyLinkedList::offsetUnset($index)

The displayed signature describes the API or identifies any correction or optional dependency. When a parameter is optional, supply it only when the task requires it.

Parameters

• index: required.

Example 1: Basic Use

The list begins with 3 values. Notice how offsetUnset changes or observes its indexed deque rather than an ordinary associative array.

<?php
$list = new SplDoublyLinkedList();
$list->push('tea');
$list->push('coffee');
$list->push('water');
$list->offsetUnset(1);
echo json_encode(iterator_to_array($list));

Output from a successful local PHP 8.4 run:

["tea","water"]

Example 2: Checking Behavior

The list begins with 4 values. Notice how offsetUnset changes or observes its indexed deque rather than an ordinary associative array.

<?php
$list = new SplDoublyLinkedList();
$list->push('one');
$list->push('two');
$list->push('three');
$list->push('four');
$list->offsetUnset(1);
echo json_encode(iterator_to_array($list));

Output from a successful local PHP 8.4 run:

["one","three","four"]

Example 3: Practical Example

The list begins with 3 values. Notice how offsetUnset changes or observes its indexed deque rather than an ordinary associative array.

<?php
$list = new SplDoublyLinkedList();
$list->push(4);
$list->push(8);
$list->push(12);
$list->offsetUnset(2);
echo json_encode(iterator_to_array($list));

Output from a successful local PHP 8.4 run:

[4,8]

Important Behavior and Edge Cases

Later numeric positions shift after removal.

Comparison with Related Approaches

Common Beginner Mistakes

Key Takeaways

• Deletes the entry at a numeric offset and closes the gap.
• Later numeric positions shift after removal.
• pop removes the end; shift removes the beginning.

Use SplDoublyLinkedList::offsetUnset when its documented behavior matches the problem. Test the relevant edge cases in your own runtime before deploying it.