3v4l.org

run code in 300+ PHP versions simultaneously
<?php $array = []; // make some array for testing for($i=0; $i < 100; $i++) $array["key$i"] = $i; for($i=0; $i < 1000000; $i++) { reset($array); $firstKey = key($array); }

preferences:
40.29 ms | 405 KiB | 5 Q