PHP CodeIgniter change object array data value from database with foreach

Use an extra variable.

$result = $data->result();
foreach ($result as &$row) {
 // enter code here
}

If I understand what you mean, you are assuming that modifing the object you are editing also values in the database.

If that's the case, you should run a query to update data in the database

$result = $data->result();
foreach ($result as &$row) {
  $row->prop = 'new value';
  $this->db->set($row)->where('id',$row->id)->update('table_name');
}

==================== EDIT ====================

If you want to ignore date like 0000-00-00 you should set it to an empty string and then print out the table.

$result = $data->result();
foreach ($result as &$row) 
{
  if( $row->date == '0000-00-00')
      $row->date = '';
}

to print out a table you can use the HTML table class of Codeigniter passing the $result object.

http://ellislab.com/codeigniter%20/user-guide/libraries/table.html

$this->load->library('table');
echo $this->table->generate($result);

For some reasons, methods, that were offered don't work. I found solution, how to solve my problem:

<?php $result = $data->result_array();
 foreach($result as &$row)
{
    if($row['date'] == '0000-00-00')
    {
        $row['date'] = ' ';
    } 
$this->table->add_row($row['date'], $row['(other parameter)']...);
}
$this->table->set_template($template); 
echo $this->table->generate(); ?>