下面的代码有两个错误。我实际上是在尝试遍历所有自定义分类法，并将它们添加到post类中。

注意：在/Applications/MAMP/htdocs/Dev/wp-includes/taxonomy中进行数组到字符串的转换。php在线3317

注意：在Applications/MAMP/htdocs/Dev/wp includes/category模板中，数组到字符串的转换。第1253行php

if ( ! function_exists(\'custom_taxonomy_class\') ) {

    function custom_taxonomy_class($classes, $class, $ID) {

       $args = array(
         \'public\'   => true,
         \'_builtin\' => false

       ); 
       $output = \'names\'; // or objects
       $operator = \'and\'; // \'and\' or \'or\'

       $taxonomies = get_taxonomies( $args, $output, $operator ); 
       $terms = get_the_terms( (int) $ID, (array)$taxonomies );

        if ( ! empty( $terms ) ) {
            foreach ( (array) $terms as $order => $term ) {            
                if ( ! in_array( $term->slug, $classes ) ) {
                    $classes[] = $term->slug;
                }
            }
        }

       $classes[] = \'\';

        return $classes;
    }
}

add_filter( \'post_class\', \'custom_taxonomy_class\', 10, 3 );