get_term_children( int $term_id, string $taxonomy )

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


Description 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 Parameters

$term_id

(int) (Required) ID of Term to get children.

$taxonomy

(string) (Required) Taxonomy Name.


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Return Return

(array|WP_Error) List of Term IDs. WP_Error returned if $taxonomy does not exist.


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Source Source

File: wp-includes/taxonomy.php

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;
}

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Changelog Changelog

Changelog
Version Description
2.3.0 Introduced.


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User Contributed Notes User Contributed Notes

  1. Skip to note content
    Contributed by Codex

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

    <?php
    $term_id = 10;
    $taxonomy_name = 'products';
    $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( $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>
    
    

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