Namen einer Kategorie anhand der ID ermitteln

/**
 * Returns the title of the category with the given ID. Equals the function
 * single_cat_title, but can return the title of any category and doesn't echo
 * it.
 * 
 * @param catId The ID of a category.
 * @return The name of the category with the given ID or an empty String.
 */
function my_the_category_name($catId) {
  if (!empty($catId)) {
    $my_cat_name = apply_filters('single_cat_title', get_the_category_by_ID(intval($catId)));
    if (!empty($my_cat_name)) {
      return strip_tags($my_cat_name);
    }
  }
  return '';
}