好的，下面是应该实现这个技巧的函数：

function modify_events_to_use_new_field() {
    $events = get_posts( array(
        \'post_type\' => \'event\',
        \'post_status\' => \'any\',
        \'posts_per_page\' => -1
    ) );

    foreach ( $events as $event ) {
        if ( preg_match(\'@^(.*) - ([^-]*)$@\', $event->post_title, $matches) ) { 
            // you\'ll have to modify the POST_META_KEY to the real name of your custom field
            update_post_meta( $event->ID, \'<POST_META_KEY>\', date(\'Ymd\', strtotime($matches[2]) ) );
        }
    }
}