Online PHP editor | refs for 6rUeW

<?php $array1 = [ ['subscribers' => 2, 'dt_date' => '2014-02-27'], ['subscribers' => 2, 'dt_date' => '2014-02-25'], ['subscribers' => 1, 'dt_date' => '2014-02-07'] ]; $array2 = [ ['unsubscribers' => 1, 'dt_date' => '2014-02-27'], ['unsubscribers' => 1, 'dt_date' => '2014-02-01'] ]; $default = array_fill_keys(['subscribers', 'unsubscribers'], 0); var_export( array_values( array_reduce( array_merge($array1, $array2), function($result, $row) use($default) { $result[$row['dt_date']] = array_merge($result[$row['dt_date']] ?? $default, $row); return $result; } ) ) );