创建一个嵌套数组

Question

我有一张如下表

• ID
  • 1
  • 2
  • 4
• 标题
  < li>主页
  • 关于
  • Deneme
• slug
  • home
  • 约
  • deneme
• 顺序
  • 1
  • 2
  • 1
• 体
  • Loremp ipsum
  • Dot sit
  • Color amet
• parent_id
  • 2
  • 0
  • 0

现在，我想从这个表创建嵌套数组。我的功能如下

public function get_nested ()
{
    $pages = $this->db->get('pages')->result_array();
    $array = array();
    foreach ($pages as $page) {
        if (! $page['parent_id']) {
            $array[$page['id']] = $page;
        }
        else {
            $array[$page['parent_id']]['children'][] = $page;

        }
    }
    return $array;
}
dump($array);

当我转储我的$ array

时

Dump => array(2) {
[2] => array(6) {
["id"] => string(1) "2"
["title"] => string(5) "About"
["slug"] => string(5) "about"
["order"] => string(1) "2"
["body"] => string(241) "Lorem ipsum dolor sit amet, consectetur adipisicing elit. Ipsam itaque cumque ullam eum atque consectetur voluptates veritatis sapiente voluptatem voluptatibus neque, commodi reprehenderit odit dignissimos omnis, veniam et deserunt incidunt!"
["parent_id"] => string(1) "0"
}
[4] => array(6) {
["id"] => string(1) "4"
["title"] => string(6) "deneme"
["slug"] => string(6) "deneme"
["order"] => string(1) "1"
["body"] => string(13) "deneme"
["parent_id"] => string(1) "0"
}
}

数组中只有2个页面列表，但有3个页面，其中一个有parent_id。没有显示parent_id的页面。所以在get_nested函数的else块中有一些错误。这个错误是什么？

Answer 1

<?php
try this:

public function get_nested ()
{
    $pages = $this->db->get('pages')->result_array();
    $array = array();
    foreach ($pages as $page) {
        if (! $page['parent_id']) {
            $array[$page['id']] = $page;
        }
        else if(isset($array[$page['parent_id']])){
            $size=sizeof($array[$page['parent_id']]);
            $array[$page['parent_id']][$size+1]= $page;

        }else{
            $array[$page['parent_id']]= $page;
        }
    }
        return $array;
    }
    dump($array);

?>

Answer 2

彻底查看你的代码，你会意识到它首次执行时（for parent_id =2），

$array[$page['parent_id']]['children'][] = $page; 

它会发现$ array [2]（$array [2] ['children'] [ ]）不存在。可能的解决方案是SORT (OrderBy) your query in ascending order of parent_id.