这个Q是a follow up to this answer 在Q上："How to exclude a specific term for the search?".

筛选出具有特定术语的帖子的4种方法

Type                | Pro                   | Contra
--------------------------------------------------------
Run a new query     | Easy to implement     | Add. Queries
                                            | Add. time to execute the DB call + processing the parsing of the results
Inside the loop     | Easy to implement     | Sometimes Add. Queries
                                            | Add. time to execute
Modify the query    | Full control          | Hard to implement
                                            | Needs a lot of knowledge (preparing, DB interaction)
Add new query parts | No perform. impact    | Hard to get around
                    | Secure
                    | Full core support

第一类imho是非选项。“类型”2和；3已经在另一个Q中得到了回答，而且两个都有一些回退。

问题：如何添加其他tax_query 使用（例如）主查询的参数pre_get_posts 过滤器

add_action( \'pre_get_posts\', \'my_exclude_terms_from_query\' );
function my_exclude_terms_from_query( $query ) {
    if ( $query->is_main_query() /* && whatever else */ ) {
        $tax_query = array (
                array(
                    \'taxonomy\' => \'category\',
                    \'terms\' => array( \'cat-slug\' ),
                    \'field\' => \'slug\',
                    \'operator\' => \'NOT IN\',
                )
        );
        $query->set( \'tax_query\', $tax_query );
    }
}