I use More Plugin (More Types, More Fields and More Taxonomy) to create custom taxonomies, post types and fields.

I've created a select control filled with taxonomies (looping through $wp_taxonomies).

What I need is to show a list of post types associated with currently selected taxonomies (I will do this by using jQuery) and I didn't figure out how to get such a list of post types. Thanks!

  • 1
    $wp_taxonomies['YOURTAXNAME']->object_type holds an array of post types that use the given taxonomy.
    – t31os
    Commented Feb 10, 2011 at 13:15

2 Answers 2


You retrieve it with $wp_taxonomies already. I just wrote it down, so you'll probably have to try a little to get the following lines of code up and running, but it should give you an idea of how it should work (see it as reference/pseudo code):

EDIT: After a note from Mike Schinkel i updated the code to make it easier to ignore built in taxonomies (see: _builtin). I hope Mike will post the example he sent me here, so his (much easier) sollution can be marked as the final approach...

// equals the following $keys
$wp_taxonomies['category'] == $wp_taxonomies[0];
$wp_taxonomies['post_tag'] == $wp_taxonomies[1];
$wp_taxonomies['nav_menu'] == $wp_taxonomies[2];
$wp_taxonomies['link_category'] == $wp_taxonomies[3];

// after $key #3 you retrieve all different registered taxonomies
$all_tax = count($wp_taxonomies)-4; // gives you the amount of reg. tax.

// Here starts the actual code
$post_types = array(); // some empty array to save your post types for further procesing
$i = 0;
foreach ( $wp_taxonomies as $tax ) {
if ( !$tax->_builtin)
  $post_type_arr = $tax[$i]->object_type; // array of post types in the current taxonomy
  foreach ( $post_type_arr as $arr ) : // loop through all post types assigned to the taxonomy
    $post_types[] .= $arr; // assign them to our array of post types
$post_types = array_unique($post_types); // drop doublettes out of the array

# expected result close to this...

# Array(
#   1 => $post_type_a,
#   2 => $post_type_b,
#   3 => $post_type_n
# );
  • 1
    Slight syntax error in your code mate, enforeach; should be endforeach;.. ;)
    – t31os
    Commented Feb 10, 2011 at 13:07
  • Thanks kaiser! With some minor changes your code was I looking for... Commented Feb 10, 2011 at 13:43
  • @Valentin & t31os: n/p. Could you please edit my code, so other people may reuse it? @Valentin: Please mark it as the sollution (Check on left side below voting). Thanks.
    – kaiser
    Commented Feb 10, 2011 at 14:32
  • See my edit above: Please do not mark it as the sollution.
    – kaiser
    Commented Feb 10, 2011 at 17:48

So this is the real solution:

function get_object_types_unique( $all_r_custom = false ) {
    $tax_object = get_taxonomies( array( '_builtin' => $all_r_custom ), 'objects' );
    if ( $all_r_custom == true )
        $tax_object = array_merge( $tax_object, get_taxonomies( array( '_builtin' => false ), 'objects' ) );

    $object_types = array();
    foreach ( $tax_object as $tax ) {
        $object_types = array_merge( $object_types, $tax->object_type );

    $object_types = array_unique( $object_types );
    return $object_types;

It allows to either retrieve only custom post/object types with get_object_types_unique() or all incl. built in object types get_object_types_unique( true ). So far there's with this function no chance to retrieve only the built in object types, because i can't see a need so far.

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