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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, $v) { array_splice($v, 0, 0, $k); return $v; }, array_keys($a), $a));
Output for 7.0.0 - 7.0.20, 7.1.0 - 7.1.33, 7.2.6 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.7
[["foo",1,2,3],["bar",5,2,3,4,3],["baz",5,2,1,6]]

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