Is it possible to use a custom field to assign the post category?

For example:

I have Genres custom field to my custom post type Tvseries.

Then i entered: Action, Drama, Comedy

Once i save or publish it, It will be assigned with those 3 categories i entered in the input/custom field.

  • You can assign multiple categories to a custom post type Tvseries directly. So why do you need the custom field Genres for?
    – Fayaz
    Jun 12, 2017 at 9:02

1 Answer 1


You should hook into save_post and set the categories using wp_set_object_terms():

// Add an action to run on post save
add_action( 'save_post', 'set_genre_on_save' );
function set_genre_on_save( $post_id ){
    // Check the post type
    if (is_single('tvseries')) {
        // Get the custom field data
        $custom_field_data = get_post_custom( $post_id );
        // Check if there is any genres entered in the metabox
        if (isset($custom_box_data['genre'])) {
            // Save the genre data (separated by comma) into an array
            $genre_array = explode( ',', $custom_box_data['genre'] );
            //Set the array values to lower case
            foreach ($genre_array as $genre){
                $genre = strtolower($genre);
            // Set the categories for these genres
            wp_set_object_terms( $post_id, $genre_array, 'category' );

You should enter the slug or the ID of your categories in the field. for example, War Movies won't work, but war-movies will work. Also there should be no white space between the values (or you have to change ',' to ' ,').

Note that this is just an example, since you didn't post any code. You might need to change some of the values such as genres to match your custom fields / post types.

  • Can we assign as child category to the parent using the above code. Can you please help with this.
    – Praveen
    Jun 30, 2021 at 5:28

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