数组合并和删除重复值

I have this foreach loop that outputs the below array, and I'm having a senior moment, I need it to return one array with no duplicate values, and I just can't it right.

foreach ( $post_groups as $post_group => $id ) {
    group = $wpdb->get_row( $wpdb->prepare("SELECT * FROM $table_name WHERE ID = %d", $id), ARRAY_A);
    $groups[$group['group_name']] = $group['group_name'] = unserialize( $group['group_users'] );
}

output:

array(2) {
    ["Registered Users"]=>
    array(1) {
    [0]=>
    string(1) "2"
  }
  ["Admin Users"]=>
  array(2) {
    [0]=>
    string(1) "1"
    [1]=>
    string(1) "2"
  }
}

Cheers

I believe the following is what you're after. Simply merge the arrays together and then ensure the result is unique.

$userIds = [
    'Registered Users' => array(1,2,3),
    'Admin Users' => array(3,4,5),
];

$allUserIds = array_unique(call_user_func_array('array_merge', $userIds));

var_dump($userIds);
/*
array(2) {
  ["Registered Users"]=>
  array(3) {
    [0]=>
    int(1)
    [1]=>
    int(2)
    [2]=>
    int(3)
  }
  ["Admin Users"]=>
  array(3) {
    [0]=>
    int(3)
    [1]=>
    int(4)
    [2]=>
    int(5)
  }
}
*/

var_dump($allUserIds);
/*
array(5) {
  [0]=>
  int(1)
  [1]=>
  int(2)
  [2]=>
  int(3)
  [4]=>
  int(4)
  [5]=>
  int(5)
}
*/

Use to php functions : array_unique(array_merge())

test code:

$userIds = array('RegisteredUsers' => array('A','a','b','B'),'AdminUsers' => array('C','c','B','d','a'));

$allUserIds = array_unique(array_merge($userIds['RegisteredUsers'],     $userIds['AdminUsers']));
echo "<br><br>";

var_dump($userIds);
var_dump($allUserIds);