PHP实现无限极分类

public function getTree($data, $pId=0){
    $tree = array();
    foreach($data as $k => $v)
    {
        if($v['pid'] == $pId)
        {
            $v['children'] = $this->getTree($data, $v['id']);
            $tree[] = $v;
        }
    }
    return $tree;
}

处理前：

array (size=4)
  0 => 
    array (size=4)
      'id' => int 1
      'pid' => int 0
      'title' => string '首页' (length=6)
      'url' => string 'index/index/index' (length=17)
  1 => 
    array (size=4)
      'id' => int 2
      'pid' => int 0
      'title' => string '系统设置' (length=12)
      'url' => string 'index/sys/setting' (length=17)
  2 => 
    array (size=4)
      'id' => int 3
      'pid' => int 2
      'title' => string '角色设置' (length=12)
      'url' => string '' (length=0)
  3 => 
    array (size=4)
      'id' => int 4
      'pid' => int 2
      'title' => string '用户设置' (length=12)
      'url' => string '' (length=0)

处理后：

array (size=2)
  0 => 
    array (size=5)
      'id' => int 1
      'pid' => int 0
      'title' => string '首页' (length=6)
      'url' => string 'index/index/index' (length=17)
      'children' => 
        array (size=0)
          empty
  1 => 
    array (size=5)
      'id' => int 2
      'pid' => int 0
      'title' => string '系统设置' (length=12)
      'url' => string 'index/sys/setting' (length=17)
      'children' => 
        array (size=2)
          0 => 
            array (size=5)
              'id' => int 3
              'pid' => int 2
              'title' => string '角色设置' (length=12)
              'url' => string '' (length=0)
              'children' => 
                array (size=0)
                  empty
          1 => 
            array (size=5)
              'id' => int 4
              'pid' => int 2
              'title' => string '用户设置' (length=12)
              'url' => string '' (length=0)
              'children' => 
                array (size=0)
                  empty