输出类别作者已经作为一个类写入（WordPress）

Question

OK, I have a very specific question that I hope someone can shed some light on.

I have a page that lists authors outputting using the following code

<?php

$display_admins = false;
$order_by = 'post_count'; // 'nicename', 'email', 'url', 'registered', 'display_name', or 'post_count'
$role = ''; // 'subscriber', 'contributor', 'editor', 'author' - leave blank for 'all'
$hide_empty = true; // hides authors with zero posts

if(!empty($display_admins)) {
    $blogusers = get_users('orderby='.$order_by.'&role='.$role);
} else {
    $admins = get_users('role=administrator');
    $exclude = array();
    foreach($admins as $ad) {
        $exclude[] = $ad->ID;
    }
    $exclude = implode(',', $exclude);
    $blogusers = get_users('exclude='.$exclude.'&orderby='.$order_by.'&role='.$role.'&order='.'DESC');
}
$authors = array();
foreach ($blogusers as $bloguser) {
    $user = get_userdata($bloguser->ID);
    if(!empty($hide_empty)) {
        $numposts = count_user_posts($user->ID);
        if($numposts < 1) continue;
    }
    $authors[] = (array) $user;
}

echo '<ul class="contributors">';
foreach($authors as $author) {
    $display_name = $author['data']->display_name;
    $avatar = get_wp_user_avatar($author['ID'], 'medium');
    $author_profile_url = get_author_posts_url($author['ID']);
    $filter = get_userdata($author['ID'])->yim;

    echo '<li><div class="home ', $filter,'  "><div class="feature-image"><a href="', $author_profile_url, '">', $avatar , '</a></div>
    <div class="post-title"><a href="', $author_profile_url, '"><h3>', $display_name, '</h3></a></div>
    </div>
    </li>';
}
echo '</ul>';
?>

(I got this from another support topic and tweaked it, although I can't remember where)

At the moment, the $filter variable is just a string I enter in the 'Yahoo IM' profile box (a dirty fix to test the filter). I'd like this to actually be a list of the categories (as slugs that I will output in to the class="" part of the loop) that the author has posted in.

I essentially want to be able to filter the authors by category that they have posted in, and the filter I'm using (Isotope) operates using the class, so outputting the categories in to the class of the markup is what I'm after.

Any suggestions gratefully received!

Answer 1

// Returns the posts made by the author
$authorPosts = get_posts("author={$author['ID']}"); 

$categoryList = array(); // reset previous values
foreach ($authorPosts as $post) {
  $postCategories = get_the_category($post->ID);

  // Add to the categories the author has posted in
  foreach ($postCategories as $category)
    $categoryList[] = $category->slug;
} 

// Removes duplicate categories
$categoryList = array_unique($categoryList);

You can then use $filter = implode(' ', $categoryList); and add it to your html.