3v4l.org

run code in 300+ PHP versions simultaneously
<?php $a = ["foo" => [1,2,3], "bar" => [5,2,3,4,3], "baz" => [5,2,1,6]]; echo json_encode(array_map(function ($k, $v) { return [$k, ...$v]; }, array_keys($a), $a));

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31.04 ms | 402 KiB | 5 Q