php-foreach.php

<?php

$array = [];
for ($i = 0; $i < 10000; $i++) {
    $array[] = $i;
}

$start = microtime(true);
foreach ($array as $k => $v) {
    $array[$k] = $v + 1;
}

echo "Completed in ", microtime(true) - $start, " Seconds\n";

$start = microtime(true);
foreach ($array as $k => &$v) {
    $v = $v + 1;
}

echo "Completed in ", microtime(true) - $start, " Seconds\n";