Wordpress開發筆記－更動文章呈現數

最近用wordpress時有需求

• 某自訂分類的文章在前台只能呈現9篇，其他則仍是後台設定的呈現篇數

查了半天，只要在theme中的functions.php（或其他需要處）加入

function modify_showcase_posts_per_page($wp_query) {
    if( get_query_var('showcase_cat_1') == null ) return;
    $wp_query->query_vars['posts_per_page'] = 9;
}
add_filter( 'pre_get_posts', 'modify_showcase_posts_per_page' );

註：pre_get_posts在Plugin API/Action Reference/pre get posts有提到，原文如下：

This hook is called after the query variable object is created, but before the actual query is run.

The pre_get_posts action gives developers access to the $query object by reference (any changes you make to $query are made directly to the original object - no return value is necessary).

該好好整理下每個action...

參考網址：
WordPress post per page (Archive)
How can i retrieve default post per page value? from settings->reading. And total number of posts?
Function Reference/query posts