How to get a category name with the ID via API

Sviluppatore
5 
function getCategoryById($categoryId) {
       $datas = $this->_getRequest("/site.json");
       $categories = $datas->apiresult->categories;
       foreach($categories as $categorie) {
         if(($categorie->id) == $categoryId) {
           return $categorie;
         }
       }