Modify and add of unlimited collection field
Suppose we are in a hook_node_view(), a hook_preprocess_node() or something and we have access to $node, and my collection field is 'field_collection_field':

&lt;?php
if (!empty($node-&gt;field_collection_field)) {
  $collection_fields = field_get_items('node', $node, 'field_collection_field');

  // Extract the field collection item ids
  $ids = array();

  foreach ($collection_field as $fc_field) {
      $ids[] = $fc_field['value'];
  }

  //Get the entities
  $collections = field_collection_item_load_multiple($ids);
  // dpm($collections); Devel output the items
  //Loop over the array - if you have more than one entity
  foreach($collections as $collection) {
    //Iterate over all member vars of the FieldCollectionItemEntity object
    foreach($collection as $key =&gt; $value) {
     // DO STUFF WITH COLLECTION FIELDS VALUES
    }
   }
 }//end if