Collections with SPL

SPL Queue

SplQueue removes items in the same order they were added.

first in first out Queue operations model work that should be handled from oldest to newest.

SPL Queue

first
spl_queue.php
Replay: real traced execution (multi-file project)
<?php
$first = "build";
$queue = new SplQueue();
$queue->enqueue($first);
$queue->enqueue("review");
$served = $queue->dequeue();
$remaining = $queue->count();

echo "first=" . $first . "\n";
echo "served=" . $served . "\n";
echo "remaining=" . $remaining . "\n";

<?php
$first = "plan";
$queue = new SplQueue();
$queue->enqueue($first);
$queue->enqueue("review");
$served = $queue->dequeue();
$remaining = $queue->count();

echo "first=" . $first . "\n";
echo "served=" . $served . "\n";
echo "remaining=" . $remaining . "\n";

<?php
$first = "ship";
$queue = new SplQueue();
$queue->enqueue($first);
$queue->enqueue("review");
$served = $queue->dequeue();
$remaining = $queue->count();

echo "first=" . $first . "\n";
echo "served=" . $served . "\n";
echo "remaining=" . $remaining . "\n";

  1. $first ← build, $queue ← SplQueue, $served ← build, $remaining ← 1

    1<?php2$first→ build = "build"; //@first="plan", "ship"3$queue→ SplQueue = new SplQueue();4$queueSplQueue->enqueue($firstbuild);5$queueSplQueue->enqueue("review");6$served→ build = $queueSplQueue->dequeue();7$remaining→ 1 = $queueSplQueue->count();89echo "first=" . $firstbuild . "\n";10echo "served=" . $servedbuild . "\n";11echo "remaining=" . $remaining1 . "\n";
    outputfirst=build
served=build
remaining=1

  1. $first ← plan, $queue ← SplQueue, $served ← plan, $remaining ← 1

    1<?php2$first→ plan = "plan";3$queue→ SplQueue = new SplQueue();4$queueSplQueue->enqueue($firstplan);5$queueSplQueue->enqueue("review");6$served→ plan = $queueSplQueue->dequeue();7$remaining→ 1 = $queueSplQueue->count();89echo "first=" . $firstplan . "\n";10echo "served=" . $servedplan . "\n";11echo "remaining=" . $remaining1 . "\n";
    outputfirst=plan
served=plan
remaining=1

  1. $first ← ship, $queue ← SplQueue, $served ← ship, $remaining ← 1

    1<?php2$first→ ship = "ship";3$queue→ SplQueue = new SplQueue();4$queueSplQueue->enqueue($firstship);5$queueSplQueue->enqueue("review");6$served→ ship = $queueSplQueue->dequeue();7$remaining→ 1 = $queueSplQueue->count();89echo "first=" . $firstship . "\n";10echo "served=" . $servedship . "\n";11echo "remaining=" . $remaining1 . "\n";
    outputfirst=ship
served=ship
remaining=1