PHP SplHeap::next() Method: Usage and Examples

Advances the heap iterator by extracting the current root.

The examples focus on the operation itself, including the important distinction: top inspects the root without extraction.

What It Does

Use the examples below to observe the behavior on a small dataset before extending it to application code.

Syntax and Return Value

SplHeap::next()

The displayed signature describes the API or identifies any correction or optional dependency. When a parameter is optional, supply it only when the task requires it.

Example 1: Basic Use

SplMaxHeap is used because the abstract SplHeap cannot be instantiated. The next call is shown on a small, inspectable dataset.

<?php
$heap = new SplMaxHeap();
$heap->insert(4);
$heap->insert(12);
$heap->insert(7);
$heap->rewind();
$before = $heap->current();
$heap->next();
echo json_encode([$before, $heap->current()]);

Output from a successful local PHP 8.4 run:

[12,7]

Example 2: Checking Behavior

SplMaxHeap is used because the abstract SplHeap cannot be instantiated. The next call is shown on a small, inspectable dataset.

<?php
$heap = new SplMaxHeap();
$heap->insert(2);
$heap->insert(9);
$heap->insert(5);
$heap->insert(1);
$heap->rewind();
$before = $heap->current();
$heap->next();
echo json_encode([$before, $heap->current()]);

Output from a successful local PHP 8.4 run:

[9,5]

Example 3: Practical Example

SplMaxHeap is used because the abstract SplHeap cannot be instantiated. The next call is shown on a small, inspectable dataset.

<?php
$heap = new SplMaxHeap();
$heap->insert(19);
$heap->insert(3);
$heap->insert(11);
$heap->rewind();
$before = $heap->current();
$heap->next();
echo json_encode([$before, $heap->current()]);

Output from a successful local PHP 8.4 run:

[19,11]

Important Behavior and Edge Cases

This removes an element; heap foreach traversal consumes the heap.

Comparison with Related Approaches

Common Beginner Mistakes

Key Takeaways

• Advances the heap iterator by extracting the current root.
• This removes an element; heap foreach traversal consumes the heap.
• top inspects the root without extraction.

Use SplHeap::next when its documented behavior matches the problem. Test the relevant edge cases in your own runtime before deploying it.