3v4l.org

run code in 300+ PHP versions simultaneously
<?php $a = new stdClass; $a->{'abc@gmail.com'} = []; $b = new stdClass; $b->{'xyz@gmail.com'} = []; $c = [$a, $b]; $arr = array_reduce($c, function ($arr, $obj) { return array_merge($arr, array_keys(get_object_vars($obj))); }, []); var_dump($arr);

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