delete a specific element within field collection programmatically

Question

This is driving me crazy it just sounds simple, but I cannot find the answer.

I have a field collection in a content type called field_collection_mine how you now while creating the node you can add elements to the field collection.

I have tried this:

$wrapper = entity_metadata_wrapper($entity_type, $entity);
$wrapper->field_collection_mine = array();
entity_save('field_collection_item',$wrapper);

The code above delete all the elements within the field collection, but that is now what I want!! I just want to delete for example the last element. E.g:

• Field Collection mine
• Element1
• Element2
• Element3

How can I for example delete just the element 3? The above code deletes all the elements, so field_collection_mine is left empty.

Answer 1

You need to grab the id of the field collection and wrap itself in an entity wrapper. Use the save method in the wrapper to do this instead of the entity_save function. E.g.

 $wrapper = entity_metadata_wrapper('field_collection_item', $entity);
 $wrapper->field_specific_field_collection_item->set("");

or:

$wrapper->field_specific_field_collection_item = array();
$wrapper->save();

Answer 2

Finally I could achieve what I wanted. What I did was this:

In my case I wanted to delete the last item within the field collection.

Take a look to this code, for beginners: remember that you must have the $entity already loaded, e.g.

// Remove the field value
unset($entity->field_salida_mercanc_a[LANGUAGE_NONE][count($entity->field_salida_mercanc_a[LANGUAGE_NONE])-1]);

// Reset the array to zero-based sequential keys
$entity->field_salida_mercanc_a[LANGUAGE_NONE] = array_values($entity->field_salida_mercanc_a[LANGUAGE_NONE]);

// Save the entity
entity_save($entity_type, $entity);

Thats all! The other way is:

// Get the node wapper
$wrapper = entity_metadata_wrapper($entity_type, $entity);
// Get the last position of the array items, thanks to the ->value() statement you can get the complete Array properties.
$field_collection_item_value = $wrapper->field_collection_mine[count($wrapper->field_collection_mine->value())-1]->value();
// Do not use 'unset' to delete the item due to is not the correct way, I use the entity_delete_multiple provided by the entity API
entity_delete_multiple('field_collection_item', array($field_collection_item_value->item_id));

The way above is good using entity_metadata_wrapper function, but with that way there is a complex bug that I do not know how to solve it, you can check it at #1880312 and after apply the patch in #9 you get the next issue.