Sample measure speed of code in PHP

measure.php

<?php

$start = microtime(true);

$numbers = array(1, 2, 3, 4, 5);
$new_numbers = array_map(function ($num) {
    return $num * $num;
}, $numbers);

print_r($new_numbers);

$end = microtime(true);

$duration = round($end - $start * 1000);

echo "Duration: $duration seconds";

$second_start = microtime(true);

$second_numbers = array(1, 2, 3, 4, 5);

$new_second_numbers = array();
foreach ($second_numbers as $number) {
    $new_second_numbers[] = $number * $number;
}

print_r($new_second_numbers);

$second_end = microtime(true);

$second_duration = round($second_end - $second_start * 1000, 2);

echo "Second duration: $second_duration seconds";