3v4l.org

run code in 500+ PHP versions simultaneously
<?php $b = ['siedemx'=>'ab', 'szescx'=>'a', 'osiemxxx'=>'abc']; array_walk($b, function($value, $key){echo"$key\n";}); array_walk($b, function($value, $key){echo strlen($key) . "\n";});

preferences:
128.42 ms | 2119 KiB | 5 Q