get_the_category_list() │ WP 1.5.1

Retrieve links to the categories to which the post belongs in either HTML list or custom format.

The function should be used inside the WordPress Loop or use the $post_id parameter (see description).

Generally used for quick, delimited (e.g. comma-separated) lists of categories, as part of a post entry meta.

For a more powerful, list-based function, see wp_list_categories().

Uses: get_category_parents(), get_the_category()
Used By: the_category()
Hooks from the function

Return

String. HTML code of category(s) links.

Usage

get_the_category_list( $separator, $parents, $post_id );
$separator(string)
Separator between the links.
Default: '' - displays links in the
    list
$parents(string)

How to show links if the current category is a child category. Can take:

  • multiple - show links to parent and child categories separately, keeping order (parent/ancestor).

  • single - show one link to the category in which the post is located, but the whole category (parent/ancestor) nesting structure becomes the anchor of the link.

Default: '' - just displays the categories to which the post belongs (no relation is taken into account)

$post_id(int)
ID of the post whose categories you want to display.
Default: false - current post ($post->ID)

Examples

0

#1 The list of categories of the current post separated by comma:

The code should be used in the WP loop:

$cats = get_the_category_list( ', ' );

echo '<p>Categories: '. $cats .'</p&gt';

We get it:

<p>Categories:
<a href="/url" rel="nofollow ugc">WordPress</a>,
<a href="/url" rel="nofollow ugc">Computers</a>,
<a href="/url" rel="nofollow ugc">Blogging</a>
</p>
0

#2 More examples

See the the_category() function description.

Notes

Changelog

Since 1.5.1 Introduced.

get_the_category_list() code WP 6.7.1

wp-includes/category-template.php 
function get_the_category_list( $separator = '', $parents = '', $post_id = false ) {
	global $wp_rewrite;

	if ( ! is_object_in_taxonomy( get_post_type( $post_id ), 'category' ) ) {
		/** This filter is documented in wp-includes/category-template.php */
		return apply_filters( 'the_category', '', $separator, $parents );
	}

	/**
	 * Filters the categories before building the category list.
	 *
	 * @since 4.4.0
	 *
	 * @param WP_Term[] $categories An array of the post's categories.
	 * @param int|false $post_id    ID of the post to retrieve categories for.
	 *                              When `false`, defaults to the current post in the loop.
	 */
	$categories = apply_filters( 'the_category_list', get_the_category( $post_id ), $post_id );

	if ( empty( $categories ) ) {
		/** This filter is documented in wp-includes/category-template.php */
		return apply_filters( 'the_category', __( 'Uncategorized' ), $separator, $parents );
	}

	$rel = ( is_object( $wp_rewrite ) && $wp_rewrite->using_permalinks() ) ? 'rel="category tag"' : 'rel="category"';

	$thelist = '';
	if ( '' === $separator ) {
		$thelist .= '<ul class="post-categories">';
		foreach ( $categories as $category ) {
			$thelist .= "\n\t<li>";
			switch ( strtolower( $parents ) ) {
				case 'multiple':
					if ( $category->parent ) {
						$thelist .= get_category_parents( $category->parent, true, $separator );
					}
					$thelist .= '<a href="' . esc_url( get_category_link( $category->term_id ) ) . '" ' . $rel . '>' . $category->name . '</a></li>';
					break;
				case 'single':
					$thelist .= '<a href="' . esc_url( get_category_link( $category->term_id ) ) . '"  ' . $rel . '>';
					if ( $category->parent ) {
						$thelist .= get_category_parents( $category->parent, false, $separator );
					}
					$thelist .= $category->name . '</a></li>';
					break;
				case '':
				default:
					$thelist .= '<a href="' . esc_url( get_category_link( $category->term_id ) ) . '" ' . $rel . '>' . $category->name . '</a></li>';
			}
		}
		$thelist .= '</ul>';
	} else {
		$i = 0;
		foreach ( $categories as $category ) {
			if ( 0 < $i ) {
				$thelist .= $separator;
			}
			switch ( strtolower( $parents ) ) {
				case 'multiple':
					if ( $category->parent ) {
						$thelist .= get_category_parents( $category->parent, true, $separator );
					}
					$thelist .= '<a href="' . esc_url( get_category_link( $category->term_id ) ) . '" ' . $rel . '>' . $category->name . '</a>';
					break;
				case 'single':
					$thelist .= '<a href="' . esc_url( get_category_link( $category->term_id ) ) . '" ' . $rel . '>';
					if ( $category->parent ) {
						$thelist .= get_category_parents( $category->parent, false, $separator );
					}
					$thelist .= "$category->name</a>";
					break;
				case '':
				default:
					$thelist .= '<a href="' . esc_url( get_category_link( $category->term_id ) ) . '" ' . $rel . '>' . $category->name . '</a>';
			}
			++$i;
		}
	}

	/**
	 * Filters the category or list of categories.
	 *
	 * @since 1.2.0
	 *
	 * @param string $thelist   List of categories for the current post.
	 * @param string $separator Separator used between the categories.
	 * @param string $parents   How to display the category parents. Accepts 'multiple',
	 *                          'single', or empty.
	 */
	return apply_filters( 'the_category', $thelist, $separator, $parents );
}

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