title: Allow multiple value in shortcode for custom meta field value in wordpress shortcode
body: <p>I have a shortcode which is working fine if iI put the single value for "rank" in shortcode. </p>
  
  <p>[coaches_list category="dummy" number="3" rank="2"]</p>
  
  <p>But I want to pass multiple values in "rank" as [coaches_list category="dummy" number="3" rank="2", "6"].</p>
  
  <p>'rank' is a numeric type custom field associated with post. </p>
  
  <p>I have searched alot on internet from last 2 days but found no result. Please let me know where I am having mistake. </p>
  
  <p>Here is the piece of shortcode I bulit:</p>
  
  <pre><code>$args = array(
          'number' =&gt; '-1',
          'orderby' =&gt; 'id',
          'order' =&gt; 'desc',
          'category' =&gt; '',
          'meta_key'    =&gt; '', 
          'rank'  =&gt; '', 
  
      ), $atts )
  );
  
   global $post;
  
  
    $html = "";
    $my_query = new WP_Query( array('post_type' =&gt; 'post',
         'posts_per_page' =&gt; $number, 'orderby' =&gt; $orderby, 'order' =&gt; $order, 'category' =&gt;$category, 'meta_key' =&gt; 'rank', 'meta_value' =&gt;  $rank ));
  
    if( $my_query-&gt;have_posts() ) : while( $my_query-&gt;have_posts() ) : $my_query-&gt;the_post();
  </code></pre>