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($tree);  '<br/>-----------------------------------------------------------------------<br/>';  // 将数据使用HTML再次展现 见图3  function tree2html($tree) {    echo '<ul>'; 

  foreach($tree as $leaf) { 

    echo '<li>' .$leaf['name']; 

    if(! emptyempty($leaf['children'])) tree2html($leaf['children']);      echo '</li>';    } 

  echo '</ul>';  } 

tree2html($tree);

以上就是本文的全部内容，希望对大家学习php程序设计有所帮助。

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