Creates categories based on cpt (parent posts only) with WordPress

create-cat-based-on-cpt.php

<?php

// creates categories based on cpt (parent posts only)
function create_categories_based_on_ctp() {
	// cpt you are coping posts from
	$cccpt_posts = array( 'post_type' => 'ctp', 'posts_per_page' => -1 );
	$cccpt_postslist = get_posts( $cccpt_posts );
	// cpt you are adding categories to
	$cccpt_cpt_destination = ''; // example: 'communites'
	$cccpt_cpt_description_description = ''; // example: 'this is for communities'
	foreach ( $cccpt_postslist as $post ) : setup_postdata( $post ); ?>
		<?php
		$ctp_post_parents = get_post_ancestors( $post->ID );
		// check if the post is not a parent
		if( $ctp_post_parents == null ) {
			// create category bassed off of post title
			wp_insert_term(
				esc_html( $post->post_title ),
				$cccpt_cpt_destination,
				array(
					'description'	=> $cccpt_cpt_description_description,
					'slug' 		=> basename( get_permalink( $post->ID ) )
				)
			);
		}
		?>
	<?php endforeach; 
	wp_reset_postdata();
}
add_action( 'admin_footer', 'create_categories_based_on_ctp' );

?>