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run code in 300+ PHP versions simultaneously
<?php $arr = [ "-1" => "item 1", "1" => "item 2", "\0-1" => "item 3", ]; print_r($arr); var_dump($arr); foreach ($arr as $k => $v) { print bin2hex($k) ."\n"; }

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57.51 ms | 406 KiB | 5 Q