Алекс Спэйс

function my_custom_excerpt( $output ) {
	if ( условие ) {
		$output = substr($output, 0, 100);
	} else if ( условие2 ) {
		$output = substr($output, 0, 200);
	}
	
	return $output;
}
add_filter( 'get_the_excerpt', 'my_custom_excerpt' );

/**
 * Add custom taxonomies
 *
 * Additional custom taxonomies can be defined here
 * http://codex.wordpress.org/Function_Reference/register_taxonomy
 */
function add_custom_taxonomies() {
	// Add new "Locations" taxonomy to Posts
	register_taxonomy('location', 'post', array(
		// Hierarchical taxonomy (like categories)
		'hierarchical' => true,
		// This array of options controls the labels displayed in the WordPress Admin UI
		'labels' => array(
			'name' => _x( 'Locations', 'taxonomy general name' ),
			'singular_name' => _x( 'Location', 'taxonomy singular name' ),
			'search_items' =>  __( 'Search Locations' ),
			'all_items' => __( 'All Locations' ),
			'parent_item' => __( 'Parent Location' ),
			'parent_item_colon' => __( 'Parent Location:' ),
			'edit_item' => __( 'Edit Location' ),
			'update_item' => __( 'Update Location' ),
			'add_new_item' => __( 'Add New Location' ),
			'new_item_name' => __( 'New Location Name' ),
			'menu_name' => __( 'Locations' ),
		),
		// Control the slugs used for this taxonomy
		'rewrite' => array(
			'slug' => 'locations', // This controls the base slug that will display before each term
			'with_front' => false, // Don't display the category base before "/locations/"
			'hierarchical' => true // This will allow URL's like "/locations/boston/cambridge/"
		),
	));
}
add_action( 'init', 'add_custom_taxonomies', 0 );