遞歸

    $array = array(
        array('id' => 1, 'pid' => 0, 'name' => '河北省'),
        array('id' => 2, 'pid' => 0, 'name' => '北京市'),
        array('id' => 3, 'pid' => 1, 'name' => '邯鄲市'),
        array('id' => 4, 'pid' => 2, 'name' => '朝陽區(qū)'),
        array('id' => 5, 'pid' => 2, 'name' => '通州區(qū)'),
        array('id' => 6, 'pid' => 4, 'name' => '望京'),
        array('id' => 7, 'pid' => 4, 'name' => '酒仙橋'),
        array('id' => 8, 'pid' => 3, 'name' => '永年區(qū)'),
        array('id' => 9, 'pid' => 1, 'name' => '武安市'),
    );


    /**
     * 遞歸實(shí)現(xiàn)無限極分類
     * @param $array 分類數(shù)據(jù)
     * @param $pid 父ID
     * @param $level 分類級別
     * @return $list 分好類的數(shù)組 直接遍歷即可 $level可以用來遍歷縮進(jìn)
     */

    function getTree($array, $pid =0, $level = 0){

        //聲明靜態(tài)數(shù)組,避免遞歸調(diào)用時(shí),多次聲明導(dǎo)致數(shù)組覆蓋
        static $list = [];
        foreach ($array as $key => $value){
            //第一次遍歷,找到父節(jié)點(diǎn)為根節(jié)點(diǎn)的節(jié)點(diǎn) 也就是pid=0的節(jié)點(diǎn)
            if ($value['pid'] == $pid){
                //父節(jié)點(diǎn)為根節(jié)點(diǎn)的節(jié)點(diǎn),級別為0，也就是第一級
                $value['level'] = $level;
                //把數(shù)組放到list中
                $list[] = $value;
                //把這個(gè)節(jié)點(diǎn)從數(shù)組中移除,減少后續(xù)遞歸消耗
                unset($array[$key]);
                //開始遞歸,查找父ID為該節(jié)點(diǎn)ID的節(jié)點(diǎn),級別則為原級別+1
                getTree($array, $value['id'], $level+1);
            }
        }
        return $list;
    }

    /*
     * 獲得遞歸完的數(shù)據(jù),遍歷生成分類
     */
    $array = getTree($array);

    foreach($array as $value){
       echo str_repeat('--', $value['level']), $value['name'].'<br />';
    }

引用

    $array = array(
        array('auth_id' => 100, 'auth_name' => '后臺(tái)首頁', 'auth_pid' => 0),
        array('auth_id' => 116, 'auth_name' => '管理員', 'auth_pid' => 0),
        array('auth_id' => 120, 'auth_name' => '管理員列表', 'auth_pid' => 116),
        array('auth_id' => 121, 'auth_name' => '管理員添加', 'auth_pid' => 116),
        array('auth_id' => 122, 'auth_name' => '數(shù)據(jù)一覽', 'auth_pid' => 100),
        array('auth_id' => 123, 'auth_name' => '更新日志', 'auth_pid' => 100),
        array('auth_id' => 124, 'auth_name' => '猜猜看', 'auth_pid' => 123),
    );


    function generateTree($data){
        //構(gòu)建一個(gè)新數(shù)組,key為自己的id,為第二步做鋪墊
        $items = array();
        foreach($data as $v){
            $items[$v['auth_id']] = $v;
        }

        $tree = array();
        foreach($items as $k => $item){

            //判斷是否是頂級分類
            if(isset($items[$item['auth_pid']])){
                $items[$item['auth_pid']]['son'][] = &$items[$k];   //引用賦值
            }else{
                $tree[] = &$items[$k];
            }
        }
        return $tree;
    }

    $data = generateTree($array);