# How to hide a field of a content type except when editing?

I'm using Drupal 7 and have a custom content type that I've given authenticated users the ability to add and edit. Instead of giving them the ability to delete nodes, I've added a Boolean checkbox titled "Delete?" to the content type that they can check when editing the node. This prevents them from deleting a node without any administrative review. Is there anyway to hide this checkbox when they're adding a new node?

Implement hook_form_alter() and check whether $form['nid']['#value'] is empty, if empty then it is creation else it is update. If creation then hide the field by setting #access property to FALSE. UPDATE : Create a custom module and use the following code with needed modification. Here is an example to hide tags field in article content type. function MYMODULE_form_alter(&$form, &$form_state,$form_id){
if($form_id=='article_node_form' && empty($form['nid']['#value'])){