The SplDoublyLinkedList class

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

Introduction

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

Class synopsis

class SplDoublyLinkedList implements Iterator, Countable, ArrayAccess, Serializable {

/* Constants */

const int IT_MODE_LIFO = 2;

const int IT_MODE_FIFO = 0;

const int IT_MODE_DELETE = 1;

const int IT_MODE_KEEP = 0;

/* Methods */

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.

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