[wordpress]プラグインを使わずにアクセスランキングを作る方法

//アクセス数の取得
function get_post_views( $postID ) {
$count_key = 'post_views_count';
$count     = get_post_meta( $postID, $count_key, true );
if ( $count == '' ) {
delete_post_meta( $postID, $count_key );
add_post_meta( $postID, $count_key, '0' );

return "0 views";
}

return $count . '';
}

//アクセス数の保存
function set_post_views( $postID ) {
$count_key = 'post_views_count';
$count     = get_post_meta( $postID, $count_key, true );
if ( $count == '' ) {
$count = 0;
delete_post_meta( $postID, $count_key );
add_post_meta( $postID, $count_key, '0' );
} else {
$count ++;
update_post_meta( $postID, $count_key, $count );
}
}

アクセス数: <?php echo get_post_views( get_the_ID() ); set_post_views( get_the_ID() ); ?>

アクセス数: <?php echo get_post_views( get_the_ID() ); ?> <?php if( !is_user_logged_in() ) { set_post_views( get_the_ID() ); } ?>

<section>
<h2>アクセスランキング</h2>
<?php
    $args = array(
    'post_type'     => 'post',  //投稿タイプ
    'numberposts'   => 10,       //表示数
    'meta_key'      => 'post_views_count',
    'orderby'       => 'meta_value_num',
    'order'         => 'DESC',
    );
    $posts = get_posts( $args );
    if($posts) : 
?>
<ul class="list_ar">
    <?php
        foreach( $posts as $post ) : setup_postdata( $post );
        $cat = get_the_category();
        $cat_id   = $cat[0]->cat_ID;
        $cat_name = $cat[0]->cat_name;
        $cat_slug = $cat[0]->category_nicename;
    ?>
 	<li>
<p class="title"><a href="<?php the_permalink(); ?>"><?php the_title(); ?></a></p>
<p class="category"><a href="/category/<?php echo $cat_slug; ?>"><?php echo $cat_name; ?></a></p>
</li>
<?php endforeach; ?>
<?php wp_reset_postdata(); ?></ul>
<?php else : ?>

アクセスランキングはまだ集計されていません。

<?php endif; ?>

</section>