Related Tags not in category

Question

I'm using this piece of code to show related posts based on the tag of the post you are viewing.

I'd like to modify is a little to exclude the related posts from the loop if they are in the same category of the post you are viewing

Reason for this is i already have a loop to show related posts in the same category, so trying to cut out the duplicates.

<?php
$tags = wp_get_post_tags($post->ID);
if ($tags) {
  $first_tag = $tags[0]->term_id;
  $args=array(
    'tag__in' => array($first_tag),
    'post__not_in' => array($post->ID),
    'showposts'=>5,
    'caller_get_posts'=>1
   );
  $my_query = new WP_Query($args);
  if( $my_query->have_posts() ) {
    while ($my_query->have_posts()) : $my_query->the_post(); ?>

        <!-- loop here -->

      <?php
    endwhile;
  }wp_reset_query();
}
?>

Thanks

Answer 1

Very similar to what you do with tags. Retrieve IDs of categories for current post:

$categories = get_the_category();
$cat_ids = array();
foreach($categories as $category)
    $cat_ids[] = $category->term_id;

Then exclude them in query:

'category__not_in' => $cat_ids,

Answer 2

What you can also do is keep a global variable that contains all post id's that you already showed in a "related articles" area, and pass that to post__not_in. This allows you to add and remove other ways to show related articles (by enabling or disabling widgets?), and always prevent duplicates.