5698,'first_name' => 'Peter','last_name' => 'Griffin'), array('id' => 4767,'first_name' => 'Ben', 'last_name' => 'Smith'), array('id' => 3809, 'first_name' => 'Joe','last_name' => 'Doe') ); $last_names = array_column($a, 'last_name', 'id'); print_r($last_names);