Limit Display Number Of Taxonomy Term

Question

I have 2 taxonomy sets product_cat and tvshows_cat.

There are 12 terms for each of them. A product may get 1 or 12 terms applied.

I use this code to show the term list in the product page:

$cats = get_the_term_list($post->ID, 'product_cat', '', '  ', ''); 
$tvcats = get_the_term_list($post->ID, 'tvshows_cat', '', '  ', ''); 

if (!empty($cats)){
    echo strip_tags($cats, '   ');
}elseif(!empty($tvcats)){
    echo strip_tags($tvcats, '    ');
}

The result is:

Action, Drama, Adventure, Biography, Animation

The problem is it doesn't have enough space to show all of the terms.

I need to limit number of terms to 2 terms.

Question

How can I limit the number of terms applied to two?

Answer 1

Instead using get_the_term_list() function, you should use get_the_terms() which will give you directly an array of terms (as get_the_term_list() is using get_the_terms() herself if you look to the source code of the function).

Then that you can build a custom function to get what you want (I will not use implode() function or any other one php function as we want only 2 terms.)

Note: You don't need strip_tags() function here

So your code will be:

// This function goes first
function get_my_terms( $post_id, $taxonomy ){
    $cats = get_the_terms( $post_id, $taxonomy );

    foreach($cats as $cat) $cats_arr[] = $cat->name;

    if ( count($cats_arr) > 1) $cats_str = $cats_arr[0] . ', ' . $cats_arr[1]; // return first 2 terms
    elseif ( count($cats_arr) == 1) $cats_str = $cats_arr[0]; // return one term
    else $cats_str = '';

    return $cats_str;
}

This code goes in function.php file of your active child theme (or theme) or any plugin files…

Then below is your code:

$cats = get_my_terms( $post->ID, 'product_cat' ); 
$tvcats = get_my_terms( $post->ID, 'tvshows_cat' ); 

// Displaying 2 categories terms max
echo $cats . $tvcats;

This code goes on your php templates file

— update — Or without function, your code will be:

// Product categories
$cats = get_the_terms( $post->ID, 'product_cat' );

foreach($cats as $cat) $cats_arr[] = $cat->name;

if ( count($cats_arr) > 1) $cats_str = $cats_arr[0] . ', ' . $cats_arr[1]; // return first 2 terms
elseif ( count($cats_arr) == 1) $cats_str = $cats_arr[0]; // return one term
else $cats_str = '';

// TV shows categories
$tvcats = get_the_terms( $post->ID, 'tvshows_cat' );

foreach($tvcats as $tvcat) $tvcat_arr[] = $tvcat->name;

if ( count($tvcat_arr) > 1) $tvcats_str = $tvcat_arr[0] . ', ' . $tvcat_arr[1]; // return first 2 terms
elseif ( count($tvcat_arr) == 1) $tvcats_str = $tvcat_arr[0]; // return one term
else $tvcats_str = '';

// The Display of 2 categories
echo $cats_str . $tvcats_str;

This code goes on your php templates files

Answer 2

We can limit the number of displayed terms with

// Add filter
add_filter( 'get_the_terms', 'wpse_limit_terms' );

// Get terms
$cats   = get_the_term_list($post->ID, 'product_cat', '', '  ', ''); 
$tvcats = get_the_term_list($post->ID, 'tvshows_cat', '', '  ', ''); 

// Remove filter
remove_filter( 'get_the_terms', 'wpse_limit_terms' );

where we define the filter callback as:

function wpse_limit_terms( $terms )
{
    // Adjust to your needs
    $length = 2;

    // Slice the terms array
    if( is_array( $terms ) && count( $terms ) > $length )   
        $terms = array_slice( $terms, $offset = 0, $length );

    return $terms;
}

Update:

It looks like OP only wants to get a comma separated list of term names.

We can alternatively do the following:

$taxonomy = 'product_cat'; // Adjust to your needs
$terms = get_the_terms( get_the_ID(), $taxonomy );
if( is_array( $terms ) && ! empty( $terms ) )
    echo join( ',', wp_list_pluck( array_slice( $terms, 0, 2 ), 'name' ) 

We could also create a general wrapper for this. Here's an untested suggestion:

/**
 * Custom wrapper
 *
 * @return string Comma seperated term attribute values
 */
function get_wpse_terms_attribute_csv( $post_id, $taxonomy, $attribute, $length = 0 )
{
    $csv = '';

    // Nothing to do for non-attributes 
    if( ! in_array( $attribute, [ 'name', 'term_id', 'slug' ] ) )
        return $csv;

    // Nothing to do if taxonomy doesn't exists
    if( ! taxonomy_exists( $taxonomy ) )
        return $csv;

    // Fetch terms
    $terms = get_the_terms( $post_id, $taxonomy );

    // Nothing to do if we don't have a non-empty array of terms 
    if( ! is_array( $terms ) || empty( $terms ) )
        return $csv;

    // Slice the array if needed
    if( (int) $length > 0 )
        $terms = array_slice( $terms, 0, (int) $length )

    // Pluck the terms array   
    $terms = wp_list_pluck( $terms, $attribute );

    // Generate a list of comma separated term attribute values 
    $csv = join( ',', $terms );

    return $csv;   
 ) 

We can then use this within the loop like:

echo get_wpse_terms_attribute_csv( 
    $post_id   = get_the_ID(), 
    $taxonomy  = 'product_cat', 
    $attribute = 'name', 
    $length    = 2 
);

Hopefully you can adjust this further to your needs!