从多维数组创建嵌套列表 [英] Create nested list from Multidimensional Array

问题描述

我在 PHP 中有一个数组，如下所示:

数组 ([0] =>大批 ([id] =>1[标题] =>标题1"[parent_id] =>空值[深度] =>0)[1] =>大批 ([id] =>2[标题] =>标题2"[parent_id] =>空值[深度] =>0)[2] =>大批 ([id] =>3[标题] =>标题3"[parent_id] =>2[深度] =>1)[3] =>大批 ([id] =>4[标题] =>标题4"[parent_id] =>2[深度] =>1)[4] =>大批 ([id] =>5[标题] =>标题5"[parent_id] =>空值[深度] =>0)[5] =>大批 ([id] =>6[标题] =>标题6"[parent_id] =>4[深度] =>2))

我想要做的是迭代这个数组并从中创建一个嵌套的

列表.所以结果应该是这样的:

<li>标题 1</li>//id = 1<li>标题2</li>//id = 2<ol><li>标题3</li>//id = 3 ->parent_id = 2<li>标题4</li>//id = 4 ->parent_id = 2<ol><li>标题6</li>//id = 6 ->parent_id = 4</ol></ol><li>标题5</li>//id = 5</ol>

我一直在想办法如何完成这项工作.但到目前为止，每一次尝试都失败了......

有谁知道我如何从这样的数组中创建这样一个嵌套的 <ol> 列表?

请注意，我对给定的数据没有任何控制权.我只是调用一个 API，它返回 json 数据，我将其转换为数组.这个数组看起来和我描述的一模一样.

解决方案

你应该使用递归:

首先是'php'语法中的数组:

大批 ('id' =>1、'标题' =>标题1"，'parent_id' =>'空值'，'深度' =>0),'1' =>大批 ('id' =>2、'标题' =>标题2"，'parent_id' =>'空值'，'深度' =>0),'2' =>大批 ('id' =>3、'标题' =>标题3"，'parent_id' =>2、'深度' =>1),'3' =>大批 ('id' =>4、'标题' =>标题4"，'parent_id' =>2、'深度' =>1),'4' =>大批 ('id' =>5、'标题' =>标题5"，'parent_id' =>'空值'，'深度' =>0),'5' =>大批 ('id' =>6、'标题' =>标题6"，'parent_id' =>4、'深度' =>0));

这里是代码:

$level = 'NULL';函数 r( $a, $level) {$r = "
";foreach ( $a 作为 $i ) {如果 ($i['parent_id'] == $level ) {$r = $r .
".$i['title'] .r( $a, $i['id'] ) ."</li>";}}$r = $r ."</ol>";返回 $r;}打印 r( $a, $level );?>

结果:

Title 1
Title 2
Title 3
</ol></li><li>Title 4<ol><li>Title 6<ol></ol></li></ol></li>/ol></li><li>标题 5<ol></ol></li></ol>

1. 标题 1\n

2. 标题 2\n
   1. 标题 3\n

   2. Title 4\n
      1. Title 6\n

3. Title 5\n

在检查为解决方案后进行编辑

避免空叶子:

function r( $a, $level) {$r = '' ;foreach ( $a 作为 $i ) {如果 ($i['parent_id'] == $level ) {$r = $r .
".$i['title'] .r( $a, $i['id'] ) ."</li>";}}return ($r==''?'':"<ol>". $r ."</ol>");}

I have an array in PHP, which looks like this:

array (
    [0] => array (
        [id] => 1
        [title] => "Title 1"
        [parent_id] => NULL
        [depth] => 0
    )
    [1] => array (
        [id] => 2
        [title] => "Title 2"
        [parent_id] => NULL
        [depth] => 0
    )
    [2] => array (
        [id] => 3
        [title] => "Title 3"
        [parent_id] => 2
        [depth] => 1
    )
    [3] => array (
        [id] => 4
        [title] => "Title 4"
        [parent_id] => 2
        [depth] => 1
    )
    [4] => array (
        [id] => 5
        [title] => "Title 5"
        [parent_id] => NULL
        [depth] => 0
    )
    [5] => array (
        [id] => 6
        [title] => "Title 6"
        [parent_id] => 4
        [depth] => 2
    )
)

What i want to do is iterate over this array and create a nested <ol> list from it. So the result should look like this:

<ol>
    <li>Title 1</li> // id = 1
    <li>Title 2</li> // id = 2
    <ol>
        <li>Title 3</li> // id = 3 -> parent_id = 2
        <li>Title 4</li> // id = 4 -> parent_id = 2
        <ol>
            <li>Title 6</li> // id = 6 -> parent_id = 4
        </ol>
    </ol>
    <li>Title 5</li> // id = 5
</ol>

I've been trying to think of a way how i could get this done. But so far every attempt failed...

Anyone any idea how i can create such a nested <ol> list from an array like that?

Please note that i do not have any control on the given data. I simply make a call to an API and it returns json data, which i convert to an array. And the array looks exactly like the one i described.

解决方案

You should use recursion:

First the array in 'php' syntax:

<?php
$a=array (
    '0' => array (
        'id' => 1,
        'title' => "Title 1",
        'parent_id' => 'NULL',
        'depth' => 0
    ),
    '1' => array (
        'id' => 2,
        'title' => "Title 2",
        'parent_id' => 'NULL',
        'depth' => 0
    ),
    '2' => array (
        'id' => 3,
        'title' => "Title 3",
        'parent_id' => 2,
        'depth' => 1
    ),
    '3' => array (
        'id' => 4,
        'title' => "Title 4",
        'parent_id' => 2,
        'depth' => 1
    ),
    '4' => array (
        'id' => 5,
        'title' => "Title 5",
        'parent_id' => 'NULL',
        'depth' => 0
    ),
    '5' => array (
        'id' => 6,
        'title' => "Title 6",
        'parent_id' => 4,
        'depth' => 0
    )
);

Here the code:

$level = 'NULL';

function r( $a, $level) {
   $r = "<ol>";
   foreach ( $a as $i ) {
       if ($i['parent_id'] == $level ) {
          $r = $r . "<li>" . $i['title'] . r( $a, $i['id'] ) . "</li>";
       }
   }
   $r = $r . "</ol>";
   return $r;
}

print r( $a, $level );

?>

The results:

<ol><li>Title 1<ol></ol></li><li>Title 2<ol><li>Title 3<ol>
</ol></li><li>Title 4<ol><li>Title 6<ol></ol></li></ol></li></ol></li><li>Title 5
<ol></ol></li></ol>

1. Title 1\n

2. Title 2\n
   1. Title 3\n

   2. Title 4\n
      1. Title 6\n

3. Title 5\n

EDITED AFTER CHECK AS SOLUTION

To avoid empty leafs:

function r( $a, $level) {
   $r = '' ;
   foreach ( $a as $i ) {
       if ($i['parent_id'] == $level ) {
          $r = $r . "<li>" . $i['title'] . r( $a, $i['id'] ) . "</li>";
       }
   }
   return ($r==''?'':"<ol>". $r . "</ol>");
}

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