duplicate XML data returned, How to list ony unique data?

[brooksh]

I'm pulling data from an xml file and I'm getting a lot of duplicates. How can I remove the duplicates from the query?

 

foreach($xml->category->subcategory as $category){
echo $category[id];
}//end foreach

[brooksh]

foreach($xml->category->subcategory as $category){

$filter_categoryid[] = trim($category['categoryId']);

}//end foreach

 

$filter_categoryid = array_unique($filter_categoryid);