html - How to list categories by shortcode in wordpress? -

could not find answer on question, easy. want display inline categories of current post shortcode , divided comma. tried below.

function genre( $atts, $content = null ) { $categories = the_category(', ');     return '<div id="genre"><b>genre: </b>' . $categories . '</div>'; }  add_shortcode("genre", "genre"); 

this returns genre:

function genre( $atts, $content = null ) { $categories = get_the_category(', ');     return '<div id="genre"><b>genre: </b>' . $categories . '</div>'; }  add_shortcode("genre", "genre"); 

this returns genre: array

function genre( $atts, $content = null ) { global $post; $categories = get_the_category_list( ', ', '', $post->id );  return '<div id="genre"><b>genre: </b>' . $categories . '</div>'; }  add_shortcode("genre", "genre"); 

source: http://wordpress.org/support/topic/how-to-list-categories-by-shortcode