get_the_category_rss( string $type = null )

检索所有文章类别，格式化后用于提要。
Retrieve all of the post categories, formatted for use in feeds.

目录锚点：#说明#参数#返回#源码

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说明（Description）

feed循环中当前post的所有类别都将被检索并添加feed标记，以便可以轻松地将它们添加到RSS2、Atom或RSS1和RSS0.91 RDF feed中。

参数（Parameters）

返回（Return）

（string）要在提要中显示的所有文章类别。

源码（Source）

/**
 * Retrieve all of the post categories, formatted for use in feeds.
 *
 * All of the categories for the current post in the feed loop, will be
 * retrieved and have feed markup added, so that they can easily be added to the
 * RSS2, Atom, or RSS1 and RSS0.91 RDF feeds.
 *
 * @since 2.1.0
 *
 * @param string $type Optional, default is the type returned by get_default_feed().
 * @return string All of the post categories for displaying in the feed.
 */
function get_the_category_rss($type = null) {
	if ( empty($type) )
		$type = get_default_feed();
	$categories = get_the_category();
	$tags = get_the_tags();
	$the_list = '';
	$cat_names = array();

	$filter = 'rss';
	if ( 'atom' == $type )
		$filter = 'raw';

	if ( !empty($categories) ) foreach ( (array) $categories as $category ) {
		$cat_names[] = sanitize_term_field('name', $category->name, $category->term_id, 'category', $filter);
	}

	if ( !empty($tags) ) foreach ( (array) $tags as $tag ) {
		$cat_names[] = sanitize_term_field('name', $tag->name, $tag->term_id, 'post_tag', $filter);
	}

	$cat_names = array_unique($cat_names);

	foreach ( $cat_names as $cat_name ) {
		if ( 'rdf' == $type )
			$the_list .= "		
";
		elseif ( 'atom' == $type )
			$the_list .= sprintf( '', esc_attr( get_bloginfo_rss( 'url' ) ), esc_attr( $cat_name ) );
		else
			$the_list .= "		
";
	}

	/**
	 * Filter all of the post categories for display in a feed.
	 *
	 * @since 1.2.0
	 *
	 * @param string $the_list All of the RSS post categories.
	 * @param string $type     Type of feed. Possible values include 'rss2', 'atom'.
	 *                         Default 'rss2'.
	 */
	return apply_filters( 'the_category_rss', $the_list, $type );
}