The SplQueue class

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

Introduction

The SplQueue class provides the main functionalities of a queue implemented using a doubly linked list by setting the iterator mode to SplDoublyLinkedList::IT_MODE_FIFO.

Class synopsis

class SplQueue extends SplDoublyLinkedList {

/* Inherited constants */

public const int SplDoublyLinkedList::IT_MODE_LIFO;

public const int SplDoublyLinkedList::IT_MODE_FIFO;

public const int SplDoublyLinkedList::IT_MODE_DELETE;

public const int SplDoublyLinkedList::IT_MODE_KEEP;

/* Methods */

public function dequeue(): mixed

public function enqueue(mixed $value): void

/* Inherited methods */

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

public function SplDoublyLinkedList::bottom(): mixed

public function SplDoublyLinkedList::count(): int

public function SplDoublyLinkedList::current(): mixed

public function SplDoublyLinkedList::getIteratorMode(): int

public function SplDoublyLinkedList::isEmpty(): bool

public function SplDoublyLinkedList::key(): int

public function SplDoublyLinkedList::next(): void

public function SplDoublyLinkedList::offsetExists(int $index): bool

public function SplDoublyLinkedList::offsetGet(int $index): mixed

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

public function SplDoublyLinkedList::offsetUnset(int $index): void

public function SplDoublyLinkedList::pop(): mixed

public function SplDoublyLinkedList::prev(): void

public function SplDoublyLinkedList::push(mixed $value): void

public function SplDoublyLinkedList::rewind(): void

public function SplDoublyLinkedList::serialize(): string

public function SplDoublyLinkedList::setIteratorMode(int $mode): int

public function SplDoublyLinkedList::shift(): mixed

public function SplDoublyLinkedList::top(): mixed

public function SplDoublyLinkedList::unserialize(string $data): void

public function SplDoublyLinkedList::unshift(mixed $value): void

public function SplDoublyLinkedList::valid(): bool

}

Examples

Example #1 SplQueue example

<?php
$q = new SplQueue();
$q[] = 1;
$q[] = 2;
$q[] = 3;
foreach ($q as $elem)  {
 echo $elem."\n";
}
?>

The above example will output:

1
2
3

Example #2 Efficiently handling tasks with SplQueue

<?php
$q = new SplQueue();
$q->setIteratorMode(SplQueue::IT_MODE_DELETE);
// ... enqueue some tasks on the queue ...
// process them
foreach ($q as $task) {
    // ... process $task ...
    // add new tasks on the queue
    $q[] = $newTask;
    // ...
}
?>

SplQueue::dequeue — Dequeues a node from the queue
SplQueue::enqueue — Adds an element to the queue

The SplQueue class

Introduction

Class synopsis

Examples

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