WordPressでユーザーを投稿の新しい順に並べ、○件ずつ投稿を表示する

functions.php

function sorted_author_posts( $authors, $posts_num ) {
	$all_posts = array();
	$sort_date = array();
	$posts_num = (int)$posts_num;
	foreach ( (array)$authors as $author ) {
		$author = (int)$author;
		$author_data = get_userdata( $author );
		$author_posts = get_posts( "posts_per_page=$posts_num&author=$author" );
		if ( $author_posts ) {
			$all_posts[$author_data->display_name] = $author_posts;
			$sort_date[$author_data->display_name] = $author_posts[0]->post_date;
		}
	}

	array_multisort( $sort_date, $all_posts );
	$all_posts = array_reverse( $all_posts );
	return $all_posts;
}

テンプレートの記述例

<?php $users = array( 1, 2 );
$users_posts = sorted_author_posts( $users, 2 );
foreach ( $users_posts as $user_name => $user_posts ) : ?>
	<h2><?php echo $user_name ?></h2>
	<ul>
<?php foreach ( $user_posts as $post ) : setup_postdata( $post ); ?>
		<li><?php the_title(); ?></li>
<?php endforeach; ?>
	</ul>
<?php endforeach; wp_reset_postdata(); ?>