wp_list_categories exclude not working

Question

I'm try to exclude a specific category from a list of categories that a custom post has (in this case 'Uncategorized' - ID: 1).

I've tried exclude:

wp_list_categories([
  'include' => wp_list_pluck(get_the_category(), 'term_id'),
  'title_li' => '',
  'exclude' => 1
]);

But it still appears. How can I make sure it never appears, even if a post is tagged 'Uncategorized'?

Answer 1

The wp_list_categories() function uses get_terms() behind the scenes, where the documentation for the exclude argument says:

If $include is non-empty, $exclude is ignored.

Instead you could try to exclude the term_id from the include values:

$include = wp_filter_object_list( 
    get_the_category(),   // Data
    [ 'term_id' => 1 ],   // Filter Data
    'NOT',                // Filter Option (exclude)
    'term_id'             // Pluck Data 
);

where we use wp_filter_object_list() to both filter and pluck. In general it could be better to check if the $include array is empty or not:

if( $include )
{
    // ... stuff above ...

    wp_list_categories( [
        'include'  => $includes,
        'title_li' => '',
    ] );

    // ... stuff below...
}

Answer 2

I build some tricky code to exclude category having ID 1. I'm trying to exclude category(ID:1) even remove from pluck also. Your code has include and exclude both parameter and this conflict the result.

//List the pluck...
$exclude_cat_id = 1;
$list_pluck = wp_list_pluck(get_the_category(), 'term_id');

//Get exlude pluck(ID:1) index...
$exclude_pluck = array_search($exclude_cat_id, $list_pluck);

//unset excluded pluck...
unset($list_pluck[$exclude_pluck]);

//Get all category except ID=1
$arrCat = wp_list_categories([
  'include' => $list_pluck,
  'title_li' => '',
  'exclude' => array($exclude_cat_id),
  'exclude_tree' => array($exclude_cat_id),
]);

Hope this help you well!

Answer 3

If my case, the only time I didn't want the list of categories to appear was if a post was 'Uncategorized'. The simplest solution in the end was just to use in_category():

if (!in_category(1)) {
    // Display the categories this post belongs to, as links
    wp_list_categories([
            'include' => wp_list_pluck(get_the_category(), 'term_id'),
            'title_li' => ''
    ]);
}

Answer 4

   $exclude = array();
   foreach (get_categories() as $category) 
   {$exclude[] = 1;}
   if (! empty($exclude)) 
   { $args .= ('' === $args) ? '' : '&';$args .= exclude='.implode(',', $exclude);}
   wp_list_categories($args);