Sometimes you'll want to make sure that posts from a certain category never implicitly show up in the Loops that you're displaying in your template. The category could be a special one that you use to denote portfolio pieces, photo posts, or whatever else you wish to remove from regular Loops.
First, you have to decide which category you want to exclude from your Loops. Note the name of the category, and then open or create your theme's functions.php file. Your functions.php file resides inside of your theme's directory and may contain some other code. Inside of functions.php, insert the following code:
add_action('pre_get_posts', 'remove_cat_from_loops');
function remove_cat_from_loops( $query ) {
if(!$query->get('suppress_filters')) {
$cat_id = get_cat_ID('Category Name');
$excluded_cats = $query->get('category__not_in');
if(is_array($excluded_cats)) {
$excluded_cats[] = $cat_id;
} else {
$excluded_cats = array($cat_id);
}
$query...