Display Commas in WordPress tags

Normally, in a WordPress post all tags are comma seperated: php, wordpress, functions.php. But what if you want to use a tag with commas in it? For instance “cafe, bar, restaurants“. Easy, create a filter in your WordPress functions.php, and display WordPress tags with commas in them.

// filter for tags with comma
// replace '--' with ', ' in the output - allow tags with comma this way
// e.g. save tag as "Fox--Peter" but display thx 2 filters like "Fox, Peter"

if(!is_admin()){ // make sure the filters are only called in the frontend
	function comma_tag_filter($tag_arr){
		$tag_arr_new = $tag_arr;
		if($tag_arr->taxonomy == 'post_tag' && strpos($tag_arr->name, '--')){
			$tag_arr_new->name = str_replace('--',', ',$tag_arr->name);
		}
		return $tag_arr_new;	
	}
	add_filter('get_post_tag', 'comma_tag_filter');

	function comma_tags_filter($tags_arr){
		$tags_arr_new = array();
		foreach($tags_arr as $tag_arr){
			$tags_arr_new[] = comma_tag_filter($tag_arr);
		}
		return $tags_arr_new;
	}
	add_filter('get_terms', 'comma_tags_filter');
	add_filter('get_the_terms', 'comma_tags_filter');
}

/*
 * (code by “Andi” on WordPress Development Stack Exchange)
 */

Now when you save a tag with a double dash (--), the double dash will be displayed as a comma (,). This is an over 5 year old enhancement request on Trac: allow commas in tag names.

Extending the filter to display custom taxonomies comma separated

get_the_taxonomies() Retrieve all taxonomies associated with a post.

Jason, founder of Pretty Code Machine, asked a question in the Advanced WordPress Facebook group about how to display a comma separate custom taxonomy.

What he wanted to create is what the featured image shows: saving one taxonomy Locations “Brattleboro, VT” and not two separate Locations taxonomies (“Brattleboro”, “VT”).

I replied and pointed him to this post and filter mentioned above.

After we had some further contact back and forth, Jason came up with the following code to include a taxonomy filter to display the comma separated custom taxonomy for Locations he needed:

<?php
// ...
// filter for tags (as a taxonomy) with comma
//  replace '--' with ', ' in the output - allow tags with comma this way
if( !is_admin() ) { // make sure the filters are only called in the frontend
	$custom_taxonomy_type = 'location'; // here goes your taxonomy type
	
	function comma_taxonomy_filter( $tag_arr ){
		global $custom_taxonomy_type;
		$tag_arr_new = $tag_arr;
		if( $tag_arr->taxonomy == $custom_taxonomy_type && strpos( $tag_arr->name, '--' ) ){
			$tag_arr_new->name = str_replace( '--' , ', ', $tag_arr->name);
		}
		return $tag_arr_new;	
	}
	add_filter( 'get_' . $custom_taxonomy_type, comma_taxonomy_filter );
	
	function comma_taxonomies_filter( $tags_arr ) {
		$tags_arr_new = array();
		foreach( $tags_arr as $tag_arr ) {
			$tags_arr_new[] = comma_taxonomy_filter( $tag_arr );
		}
		return $tags_arr_new;
	}
	add_filter( 'get_the_taxonomies', 'comma_taxonomies_filter' );
	add_filter( 'get_terms', 'comma_taxonomies_filter' );
	add_filter( 'get_the_terms', 'comma_taxonomies_filter' );
}

Pretty neat, isn’t it?! 🙂