I'm trying to change the value of a field in a view programatically but i find some problems. 

- first is  that even though I created a Global: custom text field which field id is 'nothing', It's value remain unchanged and the value is applied to a new field created at the end of the view. 

- Second is that this function creates some errors and drupal send lots of notices:

> Notice: Undefined property: stdClass::$wrapper_prefix in include()
> (line 32 of
> /my/path/sites/all/modules/views/theme/views-view-fields.tpl.php).
> 
>Notice: Undefined property: stdClass::$label_html in include() (line
> 33 of
> /my/path/sites/all/modules/views/theme/views-view-fields.tpl.php).
>
> Notice: Undefined property: stdClass::$wrapper_suffix in include()
> (line 35 of
> /my/path/sites/all/modules/views/theme/views-view-fields.tpl.php).

My code is: 

    function real_estast_sub_preprocess_views_view_fields(&$vars) {
      $view = $vars['view'];
    
      foreach ($view->field as $id => $field) {
           
        // change the global custom text content depend on result (node id)
        if ($vars['row']->nid == 1625){
          $vars['fields']['nothing']->content = '666€';
        }else{
          $vars['fields']['nothing']->content = $vars['row']->field_data_field_price_field_price_value."€/noche ";
        }
      }
    }