The SplHeap::extract() function is an inbuilt function in PHP which is used to extract a node from top of the heap and sift up.
Generally, the Heap Data Structure are of two types:
- Max-Heap: In a Max-Heap, the key present at the root node must be greatest among the keys present at all of its children. The same property must be recursively true for all sub-trees in that Binary Tree.
- Min-Heap: In a Min-Heap, the key present at the root node must be minimum among the keys present at all of its children. The same property must be recursively true for all sub-trees in that Binary Tree.
Syntax:
mixed SplHeap::extract()
Parameters: This function does not accept any parameter.
Return Value: This function returns the value of the extracted node.
Below programs illustrate the SplHeap::extract() function in PHP:
Example 1:
PHP
<?php   // Create a new empty Min Heap $heap = new SplMinHeap();   $heap->insert('System'); $heap->insert('GFG'); $heap->insert('ALGO'); $heap->insert('C'); $heap->insert('Geeks'); $heap->insert('neveropen');   echo $heap->extract();   ?> |
Output:
ALGO
Example 2:
PHP
<?php   // Create a new empty Max Heap $heap = new SplMaxHeap();   $heap->insert('System'); $heap->insert('GFG'); $heap->insert('ALGO'); $heap->insert('C'); $heap->insert('Geeks'); $heap->insert('neveropen');   echo $heap->extract();   ?> |
Output:
System
Reference: https://www.php.net/manual/en/splheap.extract.php
