简单的无限分类树

<?php
$d = array(
array( name=>‘公告‘,‘id‘=>1,‘pid‘=>0),
array( name=>‘文章‘,‘id‘=>2,‘pid‘=> 0),
array( name=>‘文章1‘,‘id‘=>3, ‘pid‘=>2),
array( name=>‘文章2‘,‘id‘=>4,‘pid‘=>2),
array( name=>‘文章1评论1‘,‘id‘=>5,‘pid‘=>3),
array( name=>‘文章2评论‘,‘id‘=>6,‘pid‘=>4),
array( name=>‘文章1评论2‘,‘id‘=>7,‘pid‘=>3),
array( name=>‘文章1评论1评论‘,‘id‘=>8,‘pid‘=>5),
);
function tree2(&$arr,$pid=0,$num=0){
foreach($arr as $k=>$v){
if($v[‘pid‘] == $pid){
echo str_repeat(‘&nbsp;‘,$num).$v[‘name‘].‘<br/>‘;
unset($arr[$k]);
tree2($arr,$v[‘id‘],$num+2);
}

}
}
tree2($d);
?>