The SplPriorityQueue class

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

Introduction

The SplPriorityQueue class provides the main functionalities of a prioritized queue, implemented using a max heap.

Note:
The order of elements with identical priority is undefined. It may differ from the order in which they have been inserted.

class SplPriorityQueue implements Iterator, Countable {

/* Constants */

public const int EXTR_BOTH;

public const int EXTR_PRIORITY;

public const int EXTR_DATA;

/* Methods */

public function compare(mixed $priority1, mixed $priority2): int

public function count(): int

public function current(): mixed

public function extract(): mixed

public function getExtractFlags(): int

public function insert(mixed $value, mixed $priority): true

public function isCorrupted(): bool

public function isEmpty(): bool

public function key(): int

public function next(): void

public function rewind(): void

public function setExtractFlags(int $flags): int

public function top(): mixed

public function valid(): bool

}

Version	Description
8.4.0	The class constants are now typed.

SplPriorityQueue::compare — Compare priorities in order to place elements correctly in the heap while sifting up
SplPriorityQueue::count — Counts the number of elements in the queue
SplPriorityQueue::current — Return current node pointed by the iterator
SplPriorityQueue::extract — Extracts a node from top of the heap and sift up
SplPriorityQueue::getExtractFlags — Get the flags of extraction
SplPriorityQueue::insert — Inserts an element in the queue by sifting it up
SplPriorityQueue::isCorrupted — Tells if the priority queue is in a corrupted state
SplPriorityQueue::isEmpty — Checks whether the queue is empty
SplPriorityQueue::key — Return current node index
SplPriorityQueue::next — Move to the next node
SplPriorityQueue::recoverFromCorruption — Recover from the corrupted state and allow further actions on the queue
SplPriorityQueue::rewind — Rewind iterator back to the start (no-op)
SplPriorityQueue::setExtractFlags — Sets the mode of extraction
SplPriorityQueue::top — Peeks at the node from the top of the queue
SplPriorityQueue::valid — Check whether the queue contains more nodes