无限级分类之查找子孙树

<?php 
header("Content-Type:text/html;charset=utf-8");
$cate=array(
    array('id'=>1,'name'=>'html','parent'=>0),
    array('id'=>2,'name'=>'javascript','parent'=>0),
    array('id'=>3,'name'=>'div+css','parent'=>0),
    array('id'=>4,'name'=>'linux','parent'=>0),
    array('id'=>5,'name'=>'mysql','parent'=>0),
    array('id'=>6,'name'=>'其他','parent'=>0),
    array('id'=>7,'name'=>'php','parent'=>0),
    array('id'=>8,'name'=>'字符串','parent'=>7),
    array('id'=>9,'name'=>'数组','parent'=>7),
    array('id'=>10,'name'=>'对象','parent'=>7),
    array('id'=>11,'name'=>'jquery','parent'=>2),
    array('id'=>12,'name'=>'ajax','parent'=>2),
    array('id'=>13,'name'=>'存储引擎','parent'=>5),
    array('id'=>14,'name'=>'事务','parent'=>5),
    array('id'=>15,'name'=>'存储过程','parent'=>5),
    array('id'=>16,'name'=>'视图','parent'=>5),
    array('id'=>17,'name'=>'基本命令','parent'=>4),
    array('id'=>18,'name'=>'网络配置','parent'=>4)
);

/*
 * 利用静态变量来做
 * static $con
 */

function findson($arr,$id=0,$lev=1){
    static $con=array();
    foreach ($arr as $v){
        if ($v['parent']==$id){
            $v['lev']=$lev;
            $con[]=$v;
            findson($arr,$v['id'],$lev+1);
        }
    }
    return $con;
}

$arr=findson($cate,0,1);


foreach ($arr as $v){
    if($v['lev']>1){
        echo str_repeat("&nbsp;&nbsp;&nbsp;&nbsp;", $v['lev']).$v['name']."<br/>";
    }else{
        echo $v['name']."<br/>";
    }
   
}


/*
 * 不用静态变量
 */

function findson($arr,$id=0,$lev=1){
    $con=array();
    foreach ($arr as $v){
        if ($v['parent']==$id){
            $v['lev']=$lev;
            $con[]=$v;
            $con=array_merge($con,findson($arr,$v['id'],$lev+1));
        }
    }
    return $con;
}

$arr=findson($cate,0,1);


foreach ($arr as $v){
    if($v['lev']>1){
        echo str_repeat("&nbsp;&nbsp;&nbsp;&nbsp;", $v['lev']).$v['name']."<br/>";
    }else{
        echo $v['name']."<br/>";
    }
     
}
?>