get_children( mixed $args = '', string $output = OBJECT )

检索post parent ID的所有子项。
Retrieve all children of the post parent ID.

说明（Description）

另见函数 get_posts()

参数（Parameters）

返回（Return）

源码（Source）

/**
 * Retrieve all children of the post parent ID.
 *
 * Normally, without any enhancements, the children would apply to pages. In the
 * context of the inner workings of WordPress, pages, posts, and attachments
 * share the same table, so therefore the functionality could apply to any one
 * of them. It is then noted that while this function does not work on posts, it
 * does not mean that it won't work on posts. It is recommended that you know
 * what context you wish to retrieve the children of.
 *
 * Attachments may also be made the child of a post, so if that is an accurate
 * statement (which needs to be verified), it would then be possible to get
 * all of the attachments for a post. Attachments have since changed since
 * version 2.5, so this is most likely unaccurate, but serves generally as an
 * example of what is possible.
 *
 * The arguments listed as defaults are for this function and also of the
 * {@link get_posts()} function. The arguments are combined with the
 * get_children defaults and are then passed to the {@link get_posts()}
 * function, which accepts additional arguments. You can replace the defaults in
 * this function, listed below and the additional arguments listed in the
 * {@link get_posts()} function.
 *
 * The 'post_parent' is the most important argument and important attention
 * needs to be paid to the $args parameter. If you pass either an object or an
 * integer (number), then just the 'post_parent' is grabbed and everything else
 * is lost. If you don't specify any arguments, then it is assumed that you are
 * in The Loop and the post parent will be grabbed for from the current post.
 *
 * The 'post_parent' argument is the ID to get the children. The 'numberposts'
 * is the amount of posts to retrieve that has a default of '-1', which is
 * used to get all of the posts. Giving a number higher than 0 will only
 * retrieve that amount of posts.
 *
 * The 'post_type' and 'post_status' arguments can be used to choose what
 * criteria of posts to retrieve. The 'post_type' can be anything, but WordPress
 * post types are 'post', 'pages', and 'attachments'. The 'post_status'
 * argument will accept any post status within the write administration panels.
 *
 * @since 2.0.0
 *
 * @see get_posts()
 * @todo Check validity of description.
 *
 * @global WP_Post $post
 *
 * @param mixed  $args   Optional. User defined arguments for replacing the defaults. Default empty.
 * @param string $output Optional. Constant for return type. Accepts OBJECT, ARRAY_A, ARRAY_N.
 *                       Default OBJECt.
 * @return array Array of children, where the type of each element is determined by $output parameter.
 *               Empty array on failure.
 */
function get_children( $args = '', $output = OBJECT ) {
	$kids = array();
	if ( empty( $args ) ) {
		if ( isset( $GLOBALS['post'] ) ) {
			$args = array('post_parent' => (int) $GLOBALS['post']->post_parent );
		} else {
			return $kids;
		}
	} elseif ( is_object( $args ) ) {
		$args = array('post_parent' => (int) $args->post_parent );
	} elseif ( is_numeric( $args ) ) {
		$args = array('post_parent' => (int) $args);
	}

	$defaults = array(
		'numberposts' => -1, 'post_type' => 'any',
		'post_status' => 'any', 'post_parent' => 0,
	);

	$r = wp_parse_args( $args, $defaults );

	$children = get_posts( $r );

	if ( ! $children )
		return $kids;

	if ( ! empty( $r['fields'] ) )
		return $children;

	update_post_cache($children);

	foreach ( $children as $key => $child )
		$kids[$child->ID] = $children[$key];

	if ( $output == OBJECT ) {
		return $kids;
	} elseif ( $output == ARRAY_A ) {
		$weeuns = array();
		foreach ( (array) $kids as $kid ) {
			$weeuns[$kid->ID] = get_object_vars($kids[$kid->ID]);
		}
		return $weeuns;
	} elseif ( $output == ARRAY_N ) {
		$babes = array();
		foreach ( (array) $kids as $kid ) {
			$babes[$kid->ID] = array_values(get_object_vars($kids[$kid->ID]));
		}
		return $babes;
	} else {
		return $kids;
	}
}

笔记（Notes）