【PHP原生】递归实现无限级分类树状展示数据

主要应用领域：无限极分类的菜单栏、对评论进行无限次追评 ...

1、数据库设计要求：每一条记录都需要存在id（主键）和pid（父用户id）字段。

2、查询数据库获取所有的记录组成的数组。

3、递归组合成新的数组

//封装成类里面的方法
//$data表示所有的记录组成的数组。&寻址增加查询效率。
public function getTree(&$data, $parentId = 0)
{
$tree = [];
foreach($data as $k => $v)
{
if($v['pid'] == $parentId)
{ //父亲找到儿子
$v['child'] = self::getTree($data, $v['id']); //封装成函数的时候，需要去掉self::这个标识。  
$tree[] = $v;
unset($data[$k]); // 释放原始数据变量
}
}
return $tree;
}

4、显示结果举例

排序前：

array(8) {
[0] => array(6) {
["id"] => int(1)
["memb_id"] => int(4)
["content"] => string(13) "回复内容1"
["add_time"] => int(1500622839)
["ask_id"] => int(1)
["pid"] => int(0)
}
[1] => array(6) {
["id"] => int(2)
["memb_id"] => int(4)
["content"] => string(13) "回复内容2"
["add_time"] => int(1500622839)
["ask_id"] => int(1)
["pid"] => int(0)
}
[2] => array(6) {
["id"] => int(3)
["memb_id"] => int(4)
["content"] => string(13) "回复内容3"
["add_time"] => int(1500622839)
["ask_id"] => int(1)
["pid"] => int(0)
}
[3] => array(6) {
["id"] => int(4)
["memb_id"] => int(4)
["content"] => string(13) "回复内容4"
["add_time"] => int(1500622839)
["ask_id"] => int(1)
["pid"] => int(1)
}
[4] => array(6) {
["id"] => int(5)
["memb_id"] => int(4)
["content"] => string(13) "回复内容5"
["add_time"] => int(1500622839)
["ask_id"] => int(1)
["pid"] => int(4)
}
[5] => array(6) {
["id"] => int(6)
["memb_id"] => int(4)
["content"] => string(13) "回复内容6"
["add_time"] => int(1500622839)
["ask_id"] => int(1)
["pid"] => int(4)
}
[6] => array(6) {
["id"] => int(7)
["memb_id"] => int(4)
["content"] => string(13) "回复内容7"
["add_time"] => int(1500622839)
["ask_id"] => int(1)
["pid"] => int(5)
}
[7] => array(6) {
["id"] => int(8)
["memb_id"] => int(4)
["content"] => string(13) "回复内容8"
["add_time"] => int(1500622839)
["ask_id"] => int(1)
["pid"] => int(6)
}
}

排序后：

array(3) {
[0] => array(7) {
["id"] => int(1)
["memb_id"] => int(4)
["content"] => string(13) "回复内容1"
["add_time"] => int(1500622839)
["ask_id"] => int(1)
["pid"] => int(0)
["child"] => array(1) {
[0] => array(7) {
["id"] => int(4)
["memb_id"] => int(4)
["content"] => string(13) "回复内容4"
["add_time"] => int(1500622839)
["ask_id"] => int(1)
["pid"] => int(1)
["child"] => array(2) {
[0] => array(7) {
["id"] => int(5)
["memb_id"] => int(4)
["content"] => string(13) "回复内容5"
["add_time"] => int(1500622839)
["ask_id"] => int(1)
["pid"] => int(4)
["child"] => array(1) {
[0] => array(7) {
["id"] => int(7)
["memb_id"] => int(4)
["content"] => string(13) "回复内容7"
["add_time"] => int(1500622839)
["ask_id"] => int(1)
["pid"] => int(5)
["child"] => array(0) {}}}
}
[1] => array(7) {
["id"] => int(6)
["memb_id"] => int(4)
["content"] => string(13) "回复内容6"
["add_time"] => int(1500622839)
["ask_id"] => int(1)
["pid"] => int(4)
["child"] => array(1) {
[0] => array(7) {
["id"] => int(8)
["memb_id"] => int(4)
["content"] => string(13) "回复内容8"
["add_time"] => int(1500622839)
["ask_id"] => int(1)
["pid"] => int(6)
["child"] => array(0) {}}}}}}}}
[1] => array(7) {
["id"] => int(2)
["memb_id"] => int(4)
["content"] => string(13) "回复内容2"
["add_time"] => int(1500622839)
["ask_id"] => int(1)
["pid"] => int(0)
["child"] => array(0) {}
}
[2] => array(7) {
["id"] => int(3)
["memb_id"] => int(4)
["content"] => string(13) "回复内容3"
["add_time"] => int(1500622839)
["ask_id"] => int(1)
["pid"] => int(0)
["child"] => array(0) {}}
}