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get_term_children()

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概述

get_term_children() 是一个递归函数，用于获取指定分类法中某个术语的所有子术语ID，并合并到一个数组中。仅适用于分层分类法。

关键要点

  • 函数返回术语ID数组或WP_Error对象，若分类法不存在则返回WP_Error
  • 参数包括必需的$term_id（整数）和$taxonomy（字符串）
  • 如果术语在分类法中不存在，返回空数组
  • 递归处理子术语，确保所有后代ID被包含
  • 仅对分层分类法（如分类目录）有效

代码示例

$termchildren = get_term_children( $term_id, $taxonomy_name );
echo '<ul>';
foreach ( $termchildren as $child ) {
    $term = get_term_by( 'id', $child, $taxonomy_name );
    echo '<li><a href="' . get_term_link( $term ) . '">' . $term->name . '</a></li>';
}
echo '</ul>';

注意事项

  • 对于分类目录，$taxonomy参数应为'category'；对于标签，应为'post_tag'
  • 如果术语存在但无子术语，函数可能返回包含该术语ID的数组（取决于实现细节）
  • 此函数替代了已弃用的get_category_children()，后者返回字符串而非数组
📄 原文内容

Merges all term children into a single array of their IDs.

Description

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.

Parameters

$term_idintrequired
ID of term to get children.
$taxonomystringrequired
Taxonomy name.

Return

array|WP_Error List of term IDs. WP_Error returned if $taxonomy does not exist.

Source

function get_term_children( $term_id, $taxonomy ) {
	if ( ! taxonomy_exists( $taxonomy ) ) {
		return new WP_Error( 'invalid_taxonomy', __( 'Invalid taxonomy.' ) );
	}

	$term_id = (int) $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;
}

View all references View on Trac View on GitHub

Uses Description
_get_term_hierarchy()wp-includes/taxonomy.php

Retrieves children of taxonomy as term IDs.
get_term_children()wp-includes/taxonomy.php

Merges all term children into a single array of their IDs.
taxonomy_exists()wp-includes/taxonomy.php

Determines whether the taxonomy name exists.
__()wp-includes/l10n.php

Retrieves the translation of $text.
WP_Error::__construct()wp-includes/class-wp-error.php

Initializes the error.

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Used by Description
WP_Term_Query::get_terms()wp-includes/class-wp-term-query.php

Retrieves the query results.
WP_Tax_Query::clean_query()wp-includes/class-wp-tax-query.php

Validates a single query.
get_term_children()wp-includes/taxonomy.php

Merges all term children into a single array of their IDs.

Changelog

Version Description
2.3.0 Introduced.

User Contributed Notes

  1. Skip to note 4 content


    Codex


    You must log in to vote on the helpfulness of this noteVote results for this note: 2You must log in to vote on the helpfulness of this note

    A Basic Example
    Used to get an array of children taxonomies and write them out with links in an unordered list.

    ';
foreach ( $termchildren as $child ) {
	$term = get_term_by( 'id', $child, $taxonomy_name );
	echo '<li><a href="' . get_term_link( $child, $taxonomy_name ) . '">' . $term->name . '</a></li>';
}
echo '</ul>';
?>

    This would return something like.

    <ul> 
<li><a href="link_to_term_page">Term 1</a></li>
<li><a href="link_to_term_page">Term 2</a></li>
</ul>

  2. Skip to note 5 content


    jon


    You must log in to vote on the helpfulness of this noteVote results for this note: 2You must log in to vote on the helpfulness of this note

    Categories and Tags are the two pre-defined Taxonomies. The Taxonomy Name, the second required parameter $taxonomy, is ‘category’ for Categories and ‘post_tag’ for Tags.

    If replacing the deprecated function get_category_children() , which returns a String, note that get_term_children() returns an array of Category IDs if the second parameter $taxonomy is ‘category’.