php无限级分类算法

function subtree($arr,$id=0,$lev=1) {

    $subs = array(); // 子孙数组

    foreach($arr as $v) {

        if($v['pid'] == $id) {

            $v['lev'] = $lev;

            $subs[] = $v; // 举例说找到array('id'=>1,'name'=>'安徽','parent'=>0),

            $subs = array_merge($subs,subtree($arr,$v['id'],$lev+1));

        }

    }

    return $subs;

}

$tree = subtree($res,0,1);

foreach ($tree as $v ) {

    echo str_repeat(' |- ',$v['lev']),$v['name'],'<br />';  //str_repeat — 重复一个字符串

}