Add the correct number of commas - php

Question

This script displays the categories of a post, but excludes the ones that the user doesn't want to show:
function exclude_post_categories($excl='', $spacer=' ') {
$categories = get_the_category($post->ID);
if (!empty($categories)) {
$exclude = $excl;
$exclude = explode(",", $exclude);
$thecount = count(get_the_category()) - count($exclude);
foreach ($categories as $cat) {
$html = '';
if (!in_array($cat->cat_ID, $exclude)) {
$html .= '<a href="' . get_category_link($cat->cat_ID) . '" ';
$html .= 'title="' . $cat->cat_name . '">' . $cat->cat_name . '</a>';
if ($thecount > 1) {
$html .= $spacer;
}
$thecount--;
echo $html;
}
}
}
}
The fuctions is triggered like this.
<?php exclude_post_categories('5', ', ');
So if a post has the categories: 1,2,3,4,5 than only 1,2,3,4 are echoed.
The script works great for the posts that have the category that is excluded (5).
The problem lies with the posts that don't have that category.
So if a post has the categories: 1,2,3,4 that those are echoed but with less commas than needed: 1,2,34
$thecount variable is always calculated wrong for the posts that don't have the category that has to be excluded.

Answer 1

Try something like this:
$existing = get_the_category();
$newcategories = array_udiff($existing,$exclude,function($e,$x) {
return $e->cat_ID != $x;
});
$as_links = array_map(function($c) {
return '<a href="'.get_category_link($c->cat_ID).'" '
.'title="'.$cat->cat_name.'">'.$cat->cat_name.'</a>';
},$newcategories);
echo implode($spacer, $as_links);
This will first strip out categories whose IDs are in the $exclude array, then convert each category to a category link, before outputting them with the separator.
EDIT: Slightly mis-read the question. This expects $exclude to be an array. Put the following line at the start:
if( !is_array($exclude)) $exclude = array($exclude);
To make it support single-value inputs as well - this way you can either specify one or many categories to exclude.

Answer 2

Found a better solution to the problem here: http://css-tricks.com/snippets/wordpress/the_category-excludes/#comment-1583708
function exclude_post_categories($exclude="",$spacer=" ",$id=false){
//allow for specifiying id in case we
//want to use the function to bring in
//another pages categories
if(!$id){
$id = get_the_ID();
}
//get the categories
$categories = get_the_category($id);
//split the exclude string into an array
$exclude = explode(",",$exclude);
//define array for storing results
$result = array();
//loop the cats
foreach($categories as $cat){
if(!in_array($cat->cat_ID,$exclude)){
$result[] = "$cat->name";
}
}
//add the spacer
$result = implode($spacer,$result);
//print out the result
echo $result;
}