alphabetical-tag-index.php

<?php
/**
 * Display alphabetical list of tags.
 * Template Name: Tag Index
 * @author Joanne Waltham
 */

remove_action( 'genesis_loop', 'genesis_do_loop' );
add_action( 'genesis_loop', 'jmw_do_tag_index_loop' );

function jmw_do_tag_index_loop() {
	
	//number of columns
	$cols = 3;
	
	//Get array of tags
	$args = array(
		'orderby' => 'name',
		'order' => 'ASC',
		'hide_empty' => TRUE,
	);

	//Get list of tags, if none then quit
	if ( ! $tags = get_tags( $args ) )
    		return;

	echo '<div class="tag-index"><h1 class="entry-title">' . get_the_title() .'</h1>';

	//Set up for first time through loop
	$prev_letter = strtoupper( $tags[0]->name[0] );
	
	//Loop through tags to find out letters in use and number of tags with that letter
      	foreach ( $tags as $tag ) {
		$first_letter = strtoupper( $tag->name[0] );
		if ( $first_letter != $prev_letter ) {
			$alphabet[ $prev_letter ] = $tag_count;
			$tag_count = 0;
		}
		$tag_count = $tag_count + 1;
		$prev_letter = $first_letter;
	}

	//Dont forget last letter in tag list
	$alphabet[ $prev_letter ] = $tag_count;

	//Create Navigation
	$letter_nav = array_keys( $alphabet );
	echo '<div class="tag-nav">';
	foreach ( $letter_nav as $letter ) {
		echo '<a href="#tag-' . $letter . '">' . $letter . ' </a>';
	}
	echo '</div>';
	
	//Set up for first time through loop
	$prev_initial = strtoupper( $tags[0]->name[0] );
	echo '<div class="index-group"><h2 id="tag-' .$prev_initial . '">' . $prev_initial . '</h2>';
	$col_num = ceil( $alphabet[ $prev_initial ] / $cols );
	$this_count = 0;
	echo '<div class="one-third first"><ul>';

	//Loop Through Tags
	foreach ( $tags as $tag ) {
		//Find out first letter of tag
		$current_initial = strtoupper( $tag->name[0] );

		//If its the first time of that letter create a heading and new section
		if ( $current_initial != $prev_initial ) {
			echo '</ul></div></div><div class="index-group"><h2 id="tag-' .$current_initial . '">' . $current_initial . '</h2>';
			//How many to one column
			$col_num = ceil( $alphabet[ $current_initial ] / $cols );
			$this_count = 0;
			echo '<div class="one-third first"><ul>';
			$col_count = 1;
		}
		//Output list of tags
		$this_count = $this_count + 1;

		echo '<li><a href="' . get_tag_link($tag->term_id) .'">' . $tag->name . '</a>&nbsp;(' . $tag->count . ')</li>';
		if ( 0 == $this_count % $col_num && $col_count < $cols ) {
			echo '</ul></div><div class="one-third"><ul>';
			$col_count = $col_count + 1;
		}

		$prev_initial = $current_initial;
	}
	echo '</ul></div></div></div>';
}

genesis();