php - 怎么递归获取文章所有的评论？？？

Question

表结构：
comment_id 评论ID
arc_id 文章ID
content 内容
parent_id 评论父节点

想要递归得到这样的数据结构：

$arr=array(

[0]=>array(
    comment_id=>1
    parent_id =>0
    ['child']=>array(
       [0]=>array(
            comment_id=>2
            parent_id =>1
         ) 
          
       [1]=>array(
            comment_id=>3
            parent_id =>2
         ) 
       [2]=>array(
            comment_id=>4
            parent_id =>1
         )   
        ........
    )
    
)

[1]=>array(
     comment_id=>5
     parent_id =>0
    ['child']=>array(
       [0]=>array(
            comment_id=>6
            parent_id =>5
         ) 
          
       [1]=>array(
            comment_id=>7
            parent_id =>5
         ) 
       [2]=>array(
            comment_id=>8
            parent_id =>7
         )   
        ........
    )
)

)

Answer 1

1. 先取出一个二维数组，其中每一项带有comment_id和parent_id字段

2. 然后使用下面的函数，将上面的二维数组转成树形结构：

<?php
$arr = [
    ['comment_id' => 1, 'parent_id' => 0],
    ['comment_id' => 2, 'parent_id' => 0],
    ['comment_id' => 3, 'parent_id' => 2],
    ['comment_id' => 4, 'parent_id' => 1],
    ['comment_id' => 5, 'parent_id' => 4],
    ['comment_id' => 6, 'parent_id' => 4],
];

function getTree($arr = []) {
    $a = array_column($a, NULL, 'comment_id');
    $tree = [];

    foreach($a as $i => &$v) {
        if(isset($items[$item['parent_id']])){
            $items[$item['parent_id']]['children'][] = &$items[$item['comment_id']];
        } else {
            $tree[] = &$items[$item['id']];
        }
    }

    return $tree;
}