3v4l.org

run code in 300+ PHP versions simultaneously
<?php $count = 100; $start = microtime(true); $a = ''; for($i = 0; $i < $count; $i++) { $a .= 'a'; } printf("#1, result is %d, done in %f\n", $y, microtime(true) - $start); $start = microtime(true); $a = ""; for($i = 0; $i < $count; $i++) { $a .= "a"; } printf("#2, result is %d, done in %f\n", $y, microtime(true) - $start);

preferences:
33.31 ms | 402 KiB | 5 Q