PHP SplPriorityQueue extract() Function

The SplPriorityQueue::extract() function is an inbuilt function in PHP which is used to extract a node from top of the heap and sift up.

Syntax:

mixed SplPriorityQueue::extract()

Parameters: This function does not accept any parameter.

Return Value: This function returns the value/priority (or both) of the extracted node depending on the extract flag. 

Example:

PHP

<?php

// Declare a class
class priorityQueue extends SplPriorityQueue {

    // Compare function to compare priority
    // queue elements
    public function compare($p1, $p2) {
        if ($p1 === $p2) return 0;
        return $p1 < $p2 ? -1 : 1;
    }
}

// Create an object of priority queue
$obj = new priorityQueue();

// Insert elements into the queue
$obj->insert("Geeks",2);
$obj->insert("GFG",1);
$obj->insert("G4G",3);
$obj->insert('G',4);

// Display the extracted element
// from priority queue
var_dump($obj->extract());

?>

Output

string(1) "G"

Reference: https://www.php.net/manual/en/splpriorityqueue.extract.php