get_page_hierarchy

Order the pages with children under parents in a flat list.

Description

(array) get_page_hierarchy( (array) &$pages, (int) $page_id = 0 );

It uses auxiliary structure to hold parent-children relationships and runs in O(N) complexity

Returns (array)

A list arranged by hierarchy. Children immediately follow their parents.

Parameters (2)

0. $pages (array) => &$pages: Posts array, passed by reference.
1. $page_id — Optional. (int): Parent page ID. Default 0.

Usage

if ( !function_exists( 'get_page_hierarchy' ) ) { 
    require_once ABSPATH . WPINC . '/post.php'; 
} 
  
// Posts array, passed by reference. 
$pages = array(); 
  
// Optional. Parent page ID. Default 0. 
$page_id = -1; 
  
// NOTICE! Understand what this does before running. 
$result = get_page_hierarchy($pages, $page_id);

Defined (1)

The function is defined in the following location(s).

/wp-includes/post.php

function get_page_hierarchy( &$pages, $page_id = 0 ) { 
    if ( empty( $pages ) ) { 
        return array(); 
    } 
 
    $children = array(); 
    foreach ( (array) $pages as $p ) { 
        $parent_id = intval( $p->post_parent ); 
        $children[ $parent_id ][] = $p; 
    } 
 
    $result = array(); 
    _page_traverse_name( $page_id, $children, $result ); 
 
    return $result; 
}