How to Exclude post from a category

Question

To exclude a category you’ll need to modify the query that’s running. Do this using the query_posts() function: http://codex.wordpress.org/Function_Reference/query_posts

First, you’ll need to get the ID of the category you want to exclude:

$exclude_category = get_term_by('name', 'collage', 'category');

Then you’ll need add the category exclusion to the query, and pass the new query to query_posts:

global $wp_query;
$args = array_merge( $wp_query->query, array( 'category__not_in' => array( $exclude_category) ) );
query_posts( $args );

Put all this right at the top of the script, just before the loop.

Hope that works for you!