PHP SplPriorityQueue::setExtractFlags() Method: Usage and Examples

Selects EXTR_DATA, EXTR_PRIORITY or EXTR_BOTH for future extraction.

The examples focus on the operation itself, including the important distinction: getExtractFlags reads the configured mode.

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

SplPriorityQueue::setExtractFlags(int $flags)

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.

Parameters

• flags: required.

Example 1: Basic Use

The queue is a max-priority queue; equal priorities have no guaranteed FIFO order. The setExtractFlags call is shown on a small, inspectable dataset.

<?php
$heap = new SplPriorityQueue();
$heap->insert('task-4', 4);
$heap->insert('task-12', 12);
$heap->insert('task-7', 7);
$heap->setExtractFlags(SplPriorityQueue::EXTR_BOTH);
echo json_encode($heap->extract());

Output from a successful local PHP 8.4 run:

{"data":"task-12","priority":12}

Example 2: Checking Behavior

The queue is a max-priority queue; equal priorities have no guaranteed FIFO order. The setExtractFlags call is shown on a small, inspectable dataset.

<?php
$heap = new SplPriorityQueue();
$heap->insert('task-2', 2);
$heap->insert('task-9', 9);
$heap->insert('task-5', 5);
$heap->insert('task-1', 1);
$heap->setExtractFlags(SplPriorityQueue::EXTR_BOTH);
echo json_encode($heap->extract());

Output from a successful local PHP 8.4 run:

{"data":"task-9","priority":9}

Example 3: Practical Example

The queue is a max-priority queue; equal priorities have no guaranteed FIFO order. The setExtractFlags call is shown on a small, inspectable dataset.

<?php
$heap = new SplPriorityQueue();
$heap->insert('task-19', 19);
$heap->insert('task-3', 3);
$heap->insert('task-11', 11);
$heap->setExtractFlags(SplPriorityQueue::EXTR_BOTH);
echo json_encode($heap->extract());

Output from a successful local PHP 8.4 run:

{"data":"task-19","priority":19}

Important Behavior and Edge Cases

The flag changes return shape, not the internal priority ordering.

Comparison with Related Approaches

Common Beginner Mistakes

Key Takeaways

• Selects EXTR_DATA, EXTR_PRIORITY or EXTR_BOTH for future extraction.
• The flag changes return shape, not the internal priority ordering.
• getExtractFlags reads the configured mode.

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