manipulating a posts categories

after a posting i have a set of categories which im using to display data on different parts of my site, but some of these TAGS need to be hidden.. the following code hides 1 category but i am unsure of how to edit this to put 3 categories in it.

<?php
foreach((get_the_category()) as $cat) {
if ($cat->cat_ID != “19”) {
echo ‘cat_ID . ‘”>’ .
$cat->cat_name . ‘, ‘;
}
}
?>