如何在wordpress php中检索标记值并将标记值设置为数组

我想检索标记值并将其设置为数组。在这里我检索值，但如何将该标记值设置为低于数组。我想不使用插件

<?php
$args = array( 'post_type' => 'campaign', 'posts_per_page' => 10 );
$loop = new WP_Query( $args );
while ( $loop->have_posts() ) : $loop->the_post();
    the_title();
    echo '<div class="entry-content">';
  $pps=apply_filters('campaign_tag', get_post_meta($post->ID, 'campaign_tag', true)); 
   echo $pps;
    echo '</div>';
endwhile;

    $type = 'post';
    $paged = get_query_var('paged') ? get_query_var('paged') : 1;
    $args=array(
      'post_type' => $type,
      'post_status' => 'publish',
      'posts_per_page' => 10,
      'ignore_sticky_posts'=> 1,
      'tag' => '',
      'paged' => $paged
    );
?>