[Wordpress delete 0 tags]

delete_zero_tags.php

<?php

function delete_zero_tags() {
  $tags = get_terms( array(
    'taxonomy' => 'post_tag',
    'hide_empty' => false,
  ));

  if ( !empty($tags) && !is_wp_error($tags) ) {
    foreach ( $tags as $tag ) {
      if ( $tag->count == 0 ) {
        wp_delete_term( $tag->term_id, 'post_tag' );
      }
    }
  }
}