3v4l.org

run code in 300+ PHP versions simultaneously
<?php $assoc = array( "a" => 1, "b" => 0, 0 => 0 ); function is_assoc($array){ $sorted = ksort($array); $sorted = array_keys($sorted); return !ctype_digit(implode('', $sorted)); } echo is_assoc($assoc); ?>

preferences:
41.06 ms | 402 KiB | 5 Q