Online PHP editor | refs for KSmm7

<?php $rrDatas = [ [], [ "asset" => 1, "person" => 1, ], [ "asset" => 2, ], [ "test" => 1, "person" => 1, ], [ "person" => 1, "banana" => "hello", "person" => 4, ], ]; $output = []; // Prepare empty output foreach($rrDatas as $inner){ foreach($inner as $key => $value){ $output[$key][] = $value; } } echo json_encode($output); // {"asset":[1,2],"person":[1]}