PHP递归实现层级树状展开

本文实例为大家分享了PHP递归实现层级树状展开的主要代码，供大家参考，具体内容如下

效果图：

实现代码：

<?php   $db = mysql_connect('localhost', 'root', 'root') or die('Can/'t connect to database'); mysql_select_db('test') or die('Can/'t find database : test'); $result = mysql_query('select id, fid, name from tree'); while($arr = mysql_fetch_array($result)){   $data[] = array(     'id' => $arr['id'],      'fid' => $arr['fid'],     'name' => $arr['name'],    ); }   // 将数据按照缩进简单排列 见图1 function data2arr($tree, $rootId = 0, $level = 0) {   foreach($tree as $leaf) {     if($leaf['fid'] == $rootId) {       echo str_repeat('    ', $level) . $leaf['id'] . ' ' . $leaf['name'] . '<br/>';       foreach($tree as $l) {         if($l['fid'] == $leaf['id']) {           data2arr($tree, $leaf['id'], $level + 1);           break;         }       }     }   } }   data2arr($data); echo '<br/>-----------------------------------------------------------------------<br/>';   // 将数据按照所属关系封装 见图2 function arr2tree($tree, $rootId = 0) {   $return = array();   foreach($tree as $leaf) {     if($leaf['fid'] == $rootId) {       foreach($tree as $subleaf) {         if($subleaf['fid'] == $leaf['id']) {           $leaf['children'] = arr2tree($tree, $leaf['id']);           break;         }       }       $return[] = $leaf;     }   }   return $return; }   $tree = arr2tree($data); print_r($tree); echo '<br/>-----------------------------------------------------------------------<br/>';   // 将数据使用HTML再次展现 见图3 function tree2html($tree) {   echo '<ul>';   foreach($tree as $leaf) {     echo '<li>' .$leaf['name'];     if(! emptyempty($leaf['children'])) tree2html($leaf['children']);     echo '</li>';   }   echo '</ul>'; }   tree2html($tree);

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