3v4l.org

run code in 300+ PHP versions simultaneously
<?php $a = ["1","2"]; $b = ["2",3=>[]]; $out = array_udiff($a, $b, function($c, $d) { static $i = 0; echo ++$i. @": $c != $d= ".$c != $d.PHP_EOL; return $c != $d; }); var_dump($out);

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30.5 ms | 402 KiB | 5 Q