Count an array of a function?

How do I echo of the result count of the following function?

public function get_Myinteresses() 
{
    global $db;
    $myInteresses = array();
    $get_interids = $db->query(sprintf("SELECT * FROM inter_user_conn WHERE iduser = %s", secure($this->_data['user_id'], 'int'))) or _error(SQL_ERROR_THROWEN);      
    if($get_interids->num_rows > 0) 
    {
        while($interids = $get_interids->fetch_assoc()) 
        {
          $nterid = $interids['idinter'];
          $get_Myinteresses = $db->query(sprintf("SELECT * FROM inter_list WHERE idinter = %s", secure($nterid, 'int') )) or _error(SQL_ERROR_THROWEN);
          if($get_Myinteresses->num_rows > 0) 
          {
              while($minteresse = $get_Myinteresses->fetch_assoc()) 
              {
                  $myInteresses[] = $minteresse;
              }
          }
        }
    }
    return $myInteresses;
}