Strip Characters From Tag Name

Question

I am having some difficulties trying to strip out special characters and spaces from my tags. Using the below code:

                <ul class="work_tags_nav">
                <li><a class="all" href="#">all.</a></li>
            <?php
                query_posts(array( 'post_type'=> 'work' ));
                if ( have_posts() ) : while ( have_posts() ) : the_post();
                    $custom_post_tags = get_the_tags();
                if ( $custom_post_tags ) {
                    foreach( $custom_post_tags as $tag ) {
                        $tags_arr[] = $tag -> name;
                    }
                }
                endwhile; endif;
                if( $tags_arr ) {
                    $uniq_tags_arr = array_unique( $tags_arr );
                 foreach( $uniq_tags_arr as $tag ) {
                     // LIST ALL THE TAGS FOR DESIRED POST TYPE
                     $sanitizeTag =  sanitize_title($tag);
                     $tag_link = get_term_by('name', $tag, 'post_tag');                                              
                     echo '<li><a class="'.$tag.'" href="javascript:void(0)">' .$tag. '.</a></li>';
                     }
                 }
             ?>
            </ul>

On this line: echo '<li><a class="'.$tag.'" href="javascript:void(0)">' .$tag. '.</a></li>';

I want the class="" to show the tag but if the tag has "&" or spaces etc. to strip them out. Any ideas?

Answer 1

Here it how you can do it.

$tag = 'medical & health';
$tag_class = preg_replace('/[^A-Za-z0-9-]+/', '-', html_entity_decode($tag));
echo '<li><a class="'.$tag_class.'" href="javascript:void(0)">' .$tag. '.</a></li>';

Answer 2

You can also use a built-in function: sanitize_title();. For more info see here.

<?php 
//returns medical-health
echo sanitize_title( 'Medical & Health' );
?>

Answer 3

Even easier (and faster) with native PHP functions:

$tag_name = filter_var( $tag_name, FILTER_SANITIZE_SPECIAL_CHARS );

To obtain post_tag links use get_tag_link(), if it is for a different taxonomy, use get_term_link() instead.

You can as well use get_the_tag_list() or get_the_term_list() to build a list of taxonomy taxons (terms, catagories, post tags).

This would look close to the following as there's one filter:

apply_filters('wp_get_object_terms', $terms, $object_ids, $taxonomies, $args);

And the callback would look something like that:

add_filter( 'wp_get_object_terms', 'wpse108491_term_links' );
function wpse108491_term_links( $terms, $object_ids, $taxonomies, $args )
{
    if ( is_admin() )
        return $links;

    remove_filter( current_filter(), __FUNCTION__ );

    foreach ( $terms as $k => $t )
        $terms[ $k ]->name = filter_var( $t->name, FILTER_SANITIZE_SPECIAL_CHARS  );

    return $links
}

Then simply call it like this:

echo get_the_term_list(
    get_the_ID(),
    'post_tag',
    '<ul><li>',
    '</li><li>',
    '</li></ul>',
);

Keep in mind that above callback isn't tested.