it's a simple, not optimized database query. It should be just a basic example and can or must be extend furthermore. Notice, „Registered Readers” are not saved via user_level in the database. This made it necessary to have a separate database query.

You have the possibility to give the function two parameters. To display only one user group you can use the parameter $userlevel. If you need to display first name and last name, then the parameter $show_fullname has to set to TRUE, otherwise it will display the user name only.

To use the function, you have to put it in your functions.php of your theme. You can call the function with the help of the PHP Plugin (z.B. Exec-PHP) or in your template.

Only administrator, only user name

<ul>
<?php fb_list_authors(10, FALSE); ?>
</ul>

All user, first and last name

<ol>
<?php fb_list_authors(); ?>
</ol>

Only reader, first and last name

<ul>
<?php fb_list_authors(1, TRUE); ?>
</ul>

The function for functions.php or directly in your template.

function fb_list_authors($userlevel = 'all', $show_fullname = true) {
	global $wpdb;

/*
 all = Display all user
 1 = subscriber
 2 = editor
 3 = author
 7 = publisher
10 = administrator
*/

if ( $userlevel == 'all' ) {
	$author_subscriper = $wpdb->get_results("SELECT * from $wpdb->usermeta WHERE meta_key = 'wp_capabilities' AND meta_value = 'a:1:{s:10:\"subscriber\";b:1;}'");
	foreach ( (array) $author_subscriper as $author ) {
		$author    = get_userdata( $author->user_id );
		$userlevel = $author->wp2_user_level;
		$name      = $author->nickname;
		if ( $show_fullname && ($author->first_name != '' && $author->last_name != '') ) {
			$name = "$author->first_name $author->last_name";
		}
		$link = '<li>' . $name . '</li>';
		echo $link;
	}

	$i = 0;
	while ( $i <= 10 ) {
		$userlevel = $i;
		$authors = $wpdb->get_results("SELECT * from $wpdb->usermeta WHERE meta_key = 'wp_user_level' AND meta_value = '$userlevel'");
		foreach ( (array) $authors as $author ) {
			$author    = get_userdata( $author->user_id );
			$userlevel = $author->wp2_user_level;
			$name      = $author->nickname;
			if ( $show_fullname && ($author->first_name != '' && $author->last_name != '') ) {
				$name = "$author->first_name $author->last_name";
			}
			$link = '<li>' . $name . '</li>';
			echo $link;
		}
		$i++;
	}
} else {
	if ($userlevel == 1) {
		$authors = $wpdb->get_results("SELECT * from $wpdb->usermeta WHERE meta_key = 'wp_capabilities' AND meta_value = 'a:1:{s:10:\"subscriber\";b:1;}'");
	} else {
		$authors = $wpdb->get_results("SELECT * from $wpdb->usermeta WHERE meta_value = '$userlevel'");
	}
	foreach ( (array) $authors as $author ) {
		$author = get_userdata( $author->user_id );
		$userlevel = $author->wp2_user_level;
		$name = $author->nickname;
		if ( $show_fullname && ($author->first_name != '' && $author->last_name != '') ) {
			$name = "$author->first_name $author->last_name";
		}
		$link  = '<li><b>' . $userlevelname[$userlevel] . '</b></li>';
		$link .= '<li>' . $name . '</li>';
		echo $link;
	}
}
}

Alternatively you can use a very small syntax. You must customize the fields of the query.

<?php
$wp_user_search = $wpdb->get_results("SELECT ID, display_name FROM $wpdb->users ORDER BY ID");

foreach ( $wp_user_search as $userid ) {
	$user_id       = (int) $userid->ID;
	$user_login    = stripslashes($userid->user_login);
	$display_name  = stripslashes($userid->display_name);

	$return  = '';
	$return .= "\t" . '<li>'. $display_name .'</li>' . "\n";

	print($return);
}
?>

In a small series of tips and hacks of creating a theme, I will show you how to add a breadcrumb navi in your theme. This kind of navi has established in many websites and is an added value to a user friendly navigation.

Just FYI; every body who doesn’t like to mess around in functions, there are also some Plugins available.

This is how it work’s

The solution without a Plugin, directly in your theme. You have to copy the following function in functions.php; so it will be available in your theme and can be used everywhere. The function will be called in your header.php for example and via CSS formated. I used the class breadcrumb . An example of my dev blog is showing in the picture above.

// breadcrump Navigation
if (!function_exists('fb_breadcrumb_nav')) {
	function fb_breadcrumb_nav() {
		if ( !is_home() || !is_front_page() ) {
			_e('<p class="breadcrumb">» <a href="') . _e( get_option('home') ) . _e('">') . bloginfo('name') . _e('</a> » ');
			if ( is_category() ) {
				single_cat_title();
				//the_category(', ');
			} elseif ( is_single() ) {
					the_category(', ') . _e(' » ') . the_title();
			} elseif ( is_page() ) {
				_e( the_title() . '</p>');
			} elseif (is_page() && $post->post_parent ) {
				_e( get_the_title($post->post_parent) );
				_e(' » ');
				_e( the_title() );
			} elseif ( is_search() ) {
				_e('Suche nach: ') . the_search_query() . _e('</p>');
			}
		}
	}
}

You can change this function above as you like of course. It is just a simple example and just explain the idea and the function. You can also adjust the structure and output by the help of Conditional Tags. This function is without any modification usable and shouldn’t provide any big problems to implement.

The mix of HTML and PHP can be confusing for some readers, but it was important for me to show the structured outline of this function. That’s why I implement HTML in my example. Of course you can use „echos“ to deliver variables.

In one’s own Account

I wish you fun with experimenting and using this solution; Feedback is also welcome.
But before you have a question, please try to understand the code first. I’m swamped in support emails and can barely answer all of them due to lack of time. I prefer to use my little free time to write about ideas, solutions on this blog. I appreciate your understanding.