Print only the array values - PHP

Question

I have the following code within a WP loop

<?php
                // Get the selected taxonomies for the post type
                $terms = get_the_terms( get_the_ID(), 'course_type' );
                $classes = array();
                if ( $terms && ! is_wp_error( $terms ) ){
                    foreach ( $terms as $term) {
                        $classes[] = $term->slug;
                    }
                }
                ?>

What I am looking to do is print only the WP_Term object slug to use in the classes.

<div class="courses-search-result standout-box-shadow <?php print_r( $classes ); ?>">

Now, I have got it working to a point and printing a value in the classes - but it is also printing the array structure:

class="courses-search-result standout-box-shadow cilex-clearfix Array
(
    [0] => apprenticeship
)
"

Am I close to getting the correct code with my PHP? My knowledge of the language is basic right now so any help would be much appreciated.

Answer 1

print_r is a function intended for debugging, not formatted output.

The simplest way to achieve what you want is using implode , which combines the values of an array into a string; and then echo to display the string.

<div class="courses-search-result standout-box-shadow <?php echo implode(' ', $classes); ?>">

Answer 2

我建议将implode()与PHP短回显标记结合使用（即<?= -在5.4或更早版本中可用，并且启用short_open_tag配置设置）：

<div class="courses-search-result standout-box-shadow <?= implode(' ', $classes ); ?>">