Update January 18, 2016: Thought I would mention that if you also want to remove the categories from the Archives drop-down, check out my How To Exclude Categories in WordPress Archives Drop-down post.
Update January 24, 2015: I discovered a bug with the code below. I added an is_admin() exception so the post listings in the admin section would still work properly. Without the exception, the Category filter would fail to work. I actually created a WordPress Support thread when I noticed it.
For the longest time I had been using the Advanced Category Excluder plug-in to keep a couple post categories from showing on the blog’s home page, RSS feed, search, and monthly archive views. Well, after my webhost upgraded the server to PHP 5.3.17 from PHP 5.2.X it broke that plug-in. After searching around for some answers, I tried out the Simply Exclude plug-in which did work; however, it had a couple issues. One problem was that if I excluded a category from showing in the archive view or the category drop-down widget, it broke the permalink for categories where the address bar would show /?cat=6 instead of /category/dentist/ for example. It also excluded the category from both the monthly archive view and the category view itself. I did some more searching around and came across this WordPress Codex article about Category Exclusion. I adapted the code there and placed the following 8 lines of code into my theme’s functions.php file (info on using a theme’s functions.php):
// 61 = Daily Tweets, 74 = Testing
$remove_cat = '-61,-74';
// remove from archives (except category archives), feeds, search, and home page, but not admin areas
if( (is_home() || is_feed() || is_search() || ( is_archive() && !is_category() )) && !is_admin()) {
set_query_var('cat', $remove_cat);
//which is merely the more elegant way to write:
//$wp_query->;set('cat', '-' . $remove_cat);
}
}
add_action('pre_get_posts', 'remove_my_categories' );
That’s all I needed to exclude those categories’ posts from showing on the home page, RSS feeds, search results, and the monthly archives! I can still select the category from the category drop-down list and view it in the category context. Needless to say, I’ve removed both of those plug-ins from my blog.
Hopefully this information will help some others out that run into a similar situation. 🙂
