php 无限分类

public function getTree(){
	//遍历数组，按照id作为键名重新组建新的数组
	$array = [
		[
			'id' => 1,
			'pid' => 0,
			'name' => "书籍"
		],
		[
			'id' => 2,
			'pid' => 0,
			'name' => "衣服"
		],
		[
			'id' => 3,
			'pid' => 0,
			'name' => "电子商品"
		],
		[
			'id' => 4,
			'pid' => 1,
			'name' => "古代书籍"
		],
		[
			'id' => 5,
			'pid' => 1,
			'name' => "近代书籍"
		],
		[
			'id' => 6,
			'pid' => 4,
			'name' => "红楼梦"
		],
		[
			'id' => 7,
			'pid' => 5,
			'name' => "莫问"
		],
		[
			'id' => 8,
			'pid' => 2,
			'name' => "男衣服"
		],
		[
			'id' => 9,
			'pid' => 2,
			'name' => "女衣服"
		],
		[
			'id' => 10,
			'pid' => 9,
			'name' => "裙子"
		],
		[
			'id' => 11,
			'pid' => 3,
			'name' => "笔记本"
		]
	];
	$new_array = [];        
	foreach($array as $v){
		$new_array[$v['id']] = $v;
	}
	//遍历新的数组，对每一个值的pid进行判断，判断新数组中是否存在键名为pid的值，如果存在，当前值为存在的pid的子节点，不存在，当前值为一级节点，添加到返回的数据中作为一级节点。这里使用引用传值是因为直接传值是不会影响到函数外边的变量值，我们这里要给一级节点添加子节点（sons），所以需要用到引用传值。
	$return_tree = [];
	foreach($new_array as $kk=>$vv){
		if(isset($new_array[$vv['pid']])){
			$new_array[$vv['pid']]['sons'][] = &$new_array[$kk];
		}else{
			$return_tree[] = &$new_array[$kk];
		}
	}
	return show(1,'获取成功',$return_tree);
}