How to exclude children categories of parent category

Question

I want to list only certain categories and exclude a particular parent and all its children. The reason is so that if a new child category is added, it won't show up by default. With wp_list_categories you also get an active class but with get_categories you don't. I would also like to somehow get an active class from it if possible.

I tried this:

$categories = get_categories(array(
    'exclude' => array(40)
));

But it still shows the children of category with ID 40.

The below code hides all the children but is a pain to try and style it whereas if I run my own loop with get_categories I can style the output much easier.

<?php wp_list_categories( array(
    'orderby'    => 'name',
    'show_count' => false,
    'exclude'    => array( 40 )
) ); ?> 

Answer 1

$categories = get_categories( array(
    'exclude_tree' => array(40)
));

In both get_categories() and wp_list_categories() you can use the exclude_tree parameter instead of exclude.

• exclude_tree
  (array|string) Array or comma/space-separated string of term ids to exclude along with all of their descendant terms. If $include is non-empty, $exclude_tree is ignored.
  Default empty array.