How to exclude/filter a tag from get_the_tag_list()

Question

Does anyone know how to exclude/filter a tag from the HTML string generated by get_the_tag_list()?

http://codex.wordpress.org/Function_Reference/get_the_tag_list

Any help much appreciated.

Answer 1

function mytheme_filter_tags( $term_links ) {
    $result = array();
    $exclude_tags = array( 'some tag', 'another tag', 'third tag' );
    foreach ( $term_links as $link ) {
        foreach ( $exclude_tags as $tag ) {
            if ( stripos( $link, $tag ) !== false ) continue 2;
        }
        $result[] = $link;
    }
    return $result;
}
add_filter( "term_links-post_tag", 'mytheme_filter_tags', 100, 1 );

// do loop stuff
echo get_the_tag_list('<p>Tags: ',', ','</p>');
// end loop stuff

remove_filter( "term_links-post_tag", 'mytheme_filter_tags', 100 );

Answer 2

This is a snippet from one of my blogs:

function get_filtered_tags($post_id) {
    // the slugs to be INCLUDED in the term list:
    $primary_tags = array( 'books', 'travel', ... ); 

    $post_tags = wp_get_object_terms($post_id, 'post_tag');

    if( ! empty( $post_tags ) ) {
        if( ! is_wp_error( $post_tags )) {
            $tag_end = __( ', ', 'twentytwelve' );
            foreach ( $post_tags as $term ) {
                $term_slug = $term->slug;
                if ( in_array( $term_slug, $primary_tags) ) {
                    if ( isset( $tag_list ) ) {
                        $tag_list .= $tag_end;
                    }
                    $tag_list .= '<a href="' . get_term_link($term_slug, 'post_tag') . 
                        '">' . $term->name . '</a>'; 
                }
            }
        }
    }

    return $tag_list;
}

If you want to exclude $primary_tags do the following instead:

if ( ! in_array( $term_slug, $primary_tags) ) {
    ... 
}

I.e. add a ! before in_array( ... ).

Answer 3

get_the_tag_list calls get_the_term_list which then calls get_the_terms that has a filter named get_the_terms so you can use that filter to exclude your tags:

//add filter
add_filter( 'get_the_terms', 'exclude_terms_48735', 10, 1 );
//function to do filtering
function exclude_terms_48735( $terms ) {
    //list the unwanted terms ids
    $blacklist_terms = array( 1,2,3);
    // loop through the terms
    foreach( $terms as $k => $term ) {
        //only remove term if it's ID is in the array.
        if(in_array( $term->term_id, $blacklist_terms, true )) 
            unset( $terms[$k] );
    }
    return $terms;
}