PHP SplPriorityQueue compare() Function Last Updated : 22 Apr, 2021 Summarize Comments Improve Suggest changes Share Like Article Like Report The SplPriorityQueue::compare() function is an inbuilt function in PHP which is used to compare the priority queue elements to place at a particular order in the heap data structure. Syntax: int SplPriorityQueue::compare( mixed $priority1 , mixed $priority2 ) Parameters: This function accepts two parameters as mentioned above and described below: priority1: This parameter holds the priority of the first node that is being compared. priority2: This parameter holds the priority of the second node that is being compared. Return Value: This function returns the result of the comparison function. It returns +ve integer if priority1 is greater than priority2, 0 if both are equal and -ve integer otherwise. Example: PHP <?php // Declare a class class priorityQueue extends SplPriorityQueue { // Compare function to compare priority // queue elements public function compare($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); $obj->insert('G',4); // Display the priority queue elements var_dump($obj); ?> Outputobject(priorityQueue)#1 (3) { ["flags":"SplPriorityQueue":private]=> int(1) ["isCorrupted":"SplPriorityQueue":private]=> bool(false) ["heap":"SplPriorityQueue":private]=> array(4) { [0]=> array(2) { ["data"]=> string(1) "G" ["priority"]=> int(4) } [1]=> array(2) { ["data"]=> string(3) "G4G" ["priority"]=> int(3) } [2]=> array(2) { ["data"]=> string(5) "Geeks" ["priority"]=> int(2) } [3]=> array(2) { ["data"]=> string(3) "GFG" ["priority"]=> int(1) } } } Reference: https://www.php.net/manual/en/splpriorityqueue.compare.php Comment More infoAdvertise with us Next Article PHP SplPriorityQueue next() Function A ashokjaiswal Follow Improve Article Tags : Web Technologies PHP PHP-function Similar Reads PHP SplPriorityQueue count() Function The SplPriorityQueue::count() function is an inbuilt function in PHP which is used to count the number of elements in the queue. Syntax: int SplPriorityQueue::count() Parameters: This function does not accept any parameters. Return Value: This function returns the number of elements in the queue. Ex 1 min read PHP SplPriorityQueue current() Function The SplPriorityQueue::current() function is an inbuilt function in PHP which is used to return the current node pointed by the iterator. Syntax: mixed SplPriorityQueue::current() Parameters: This function does not accept any parameter. Return Value: This function returns the value/priority of the cu 1 min read 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) 1 min read PHP SplPriorityQueue key() Function The SplPriorityQueue::key() function is an inbuilt function in PHP that is used to return the current node index. Syntax: mixed SplPriorityQueue::key() Parameters: This function does not accept any parameter. Return Value: This function returns the current node index. Example: PHP <?php // Declar 1 min read PHP SplPriorityQueue next() Function The SplPriorityQueue::next() function is an inbuilt function in PHP that is used to extract the top node from the queue. Syntax: void SplPriorityQueue::next() Parameters: This function does not accept any parameter. Return Value: This function does not return any value. Example: PHP <?php // Decl 1 min read PHP SplPriorityQueue insert() Function The SplPriorityQueue::insert() function is an inbuilt function in PHP which is used to inserts an element in the queue by sifting the elements. Insert elements in priority queue by given priority. Syntax: bool SplPriorityQueue::insert( mixed $value, mixed $priority ) Parameters: This function accept 2 min read Like