noindex a specific page in WordPress using functions file

If you have one single page that you need to stop Google indexing, this the following code is how you fulfil that task.

function add_noindex_to_locations_pages() {
if ( strpos( $_SERVER['REQUEST_URI'], '/category/locations/' ) !== false ) {
echo '';
}
}
add_action( 'wp_head', 'add_noindex_to_locations_pages' );