How do use hook_views_pre_render() to modify view fields

Question

Want to use hook_views_pre_render() to modify a field in view based upon data in another field. Starting with this code:

function sbn_views_pre_render(ViewExecutable $view) {
  drupal_set_message($view->id());
    foreach ($view->result as $key => $value) {
    // How do I select fields I need?
    }
}

What I don't know how to do is select the fields I want to work with from the $view object.

Some of the things I've tried so far:

kint($value->_entity->get('id')->value);

drupal_set_message($value->_object->get('id')->value);

drupal_set_message($value->get('id')->get(0));

drupal_set_message($value->get('parent_id')->getValue()['0']['value']);

Can someone tell me, or point me to documentation which will explain?

Thanks!

Answer 1

Found the answer:

// https://drupal.stackexchange.com/questions/272495/how-to-get-views-field-names-values-for-hook-views-pre-render
foreach ($view->result as $key => $value) {
  //- Get parent_id value 
  $parent_id_value =  $value->_entity->parent_id->getValue()[0]['value'];
  //- Get parent_type value
  $parent_type_value =  $value->_entity->parent_type->getValue()[0]['value'];
  drupal_set_message($parent_id_value .' | '.$parent_type_value);
}