get_term_children( int $term_id, string $taxonomy )

将所有术语子项合并到其ID的单个数组中。
Merge all term children into a single array of their IDs.

目录锚点：#说明#参数#返回#源码#笔记

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说明（Description）

这个递归函数将把$term的所有子项合并到同一个term id数组中。仅适用于分级的分类法。

如果$term在$taxonomy中不存在，则返回空数组。

参数（Parameters）

返回（Return）

（array|WP_Error）术语ID列表。如果$taxonomy不存在，则返回WP_Error。

源码（Source）

/**
 * Merge all term children into a single array of their IDs.
 *
 * This recursive function will merge all of the children of $term into the same
 * array of term IDs. Only useful for taxonomies which are hierarchical.
 *
 * Will return an empty array if $term does not exist in $taxonomy.
 *
 * @since 2.3.0
 *
 * @param string $term_id  ID of Term to get children.
 * @param string $taxonomy Taxonomy Name.
 * @return array|WP_Error List of Term IDs. WP_Error returned if `$taxonomy` does not exist.
 */
function get_term_children( $term_id, $taxonomy ) {
	if ( ! taxonomy_exists($taxonomy) )
		return new WP_Error('invalid_taxonomy', __('Invalid taxonomy'));

	$term_id = intval( $term_id );

	$terms = _get_term_hierarchy($taxonomy);

	if ( ! isset($terms[$term_id]) )
		return array();

	$children = $terms[$term_id];

	foreach ( (array) $terms[$term_id] as $child ) {
		if ( $term_id == $child ) {
			continue;
		}

		if ( isset($terms[$child]) )
			$children = array_merge($children, get_term_children($child, $taxonomy));
	}

	return $children;
}

笔记（Notes）

一个基本的例子