The SplDoublyLinkedList class

Introduction

(PHP 5 >= 5.3.0, PHP 7, PHP 8)

The SplDoublyLinkedList class provides the main functionalities of a doubly linked list.

Class synopsis

public add(int $index, mixed $value): void

public bottom(): mixed

public count(): int

public current(): mixed

public getIteratorMode(): int

public isEmpty(): bool

public key(): int

public next(): void

public offsetExists(int $index): bool

public offsetGet(int $index): mixed

public offsetSet(?int $index, mixed $value): void

public offsetUnset(int $index): void

public pop(): mixed

public prev(): void

public push(mixed $value): void

public rewind(): void

public serialize(): string

public setIteratorMode(int $mode): int

public shift(): mixed

public top(): mixed

public unserialize(string $data): void

public unshift(mixed $value): void

public valid(): bool

Predefined Constants

Iteration Direction

SplDoublyLinkedList::IT_MODE_LIFO

The list will be iterated in a last in, first out order, like a stack.

SplDoublyLinkedList::IT_MODE_FIFO

The list will be iterated in a first in, first out order, like a queue.

Iteration Behavior

SplDoublyLinkedList::IT_MODE_DELETE

Iteration will remove the iterated elements.

SplDoublyLinkedList::IT_MODE_KEEP

Iteration will not remove the iterated elements.

Table of Contents

• SplDoublyLinkedList::add — Add/insert a new value at the specified index
• SplDoublyLinkedList::bottom — Peeks at the node from the beginning of the doubly linked list
• SplDoublyLinkedList::count — Counts the number of elements in the doubly linked list
• SplDoublyLinkedList::current — Return current array entry
• SplDoublyLinkedList::getIteratorMode — Returns the mode of iteration
• SplDoublyLinkedList::isEmpty — Checks whether the doubly linked list is empty
• SplDoublyLinkedList::key — Return current node index
• SplDoublyLinkedList::next — Move to next entry
• SplDoublyLinkedList::offsetExists — Returns whether the requested $index exists
• SplDoublyLinkedList::offsetGet — Returns the value at the specified $index
• SplDoublyLinkedList::offsetSet — Sets the value at the specified $index to $value
• SplDoublyLinkedList::offsetUnset — Unsets the value at the specified $index
• SplDoublyLinkedList::pop — Pops a node from the end of the doubly linked list
• SplDoublyLinkedList::prev — Move to previous entry
• SplDoublyLinkedList::push — Pushes an element at the end of the doubly linked list
• SplDoublyLinkedList::rewind — Rewind iterator back to the start
• SplDoublyLinkedList::serialize — Serializes the storage
• SplDoublyLinkedList::setIteratorMode — Sets the mode of iteration
• SplDoublyLinkedList::shift — Shifts a node from the beginning of the doubly linked list
• SplDoublyLinkedList::top — Peeks at the node from the end of the doubly linked list
• SplDoublyLinkedList::unserialize — Unserializes the storage
• SplDoublyLinkedList::unshift — Prepends the doubly linked list with an element
• SplDoublyLinkedList::valid — Check whether the doubly linked list contains more nodes