<?php

$nodesArrays = [['id' => 1, 'pid' => 0, 'name' => 'a'],['id' => 2, 'pid' => 0, 'name' => 'b'],['id' => 3, 'pid' => 1, 'name' => 'c'],['id' => 4, 'pid' => 2, 'name' => 'd'],['id' => 5, 'pid' => 6, 'name' => 'e'],['id' => 6, 'pid' => 4, 'name' => 'f'],['id' => 7, 'pid' => 6, 'name' => 'g'],['id' => 8, 'pid' => 6, 'name' => 'h'],['id' => 9, 'pid' => 10, 'name' => 'i'],['id' => 10, 'pid' => 8, 'name' => 'j'],['id' => 12, 'pid' => 6, 'name' => 'l'],['id' => 15, 'pid' => 7, 'name' => 'm'],];

$nodesArray1 = [

['id' => 1, 'pid' => 4, 'name' => 'a'],['id' => 2, 'pid' => 0, 'name' => 'b'],['id' => 3, 'pid' => 1, 'name' => 'c'],['id' => 4, 'pid' => 2, 'name' => 'd'],['id' => 5, 'pid' => 6, 'name' => 'e'],['id' => 6, 'pid' => 4, 'name' => 'f'],['id' => 7, 'pid' => 6, 'name' => 'g'],['id' => 8, 'pid' => 6, 'name' => 'h'],['id' => 9, 'pid' => 10, 'name' => 'i'],['id' => 10, 'pid' => 8, 'name' => 'j'],['id' => 12, 'pid' => 6, 'name' => 'l'],['id' => 15, 'pid' => 7, 'name' => 'm'],];

//换个思路 ，不改变源数据，新创建一个根节点，一个子节点树

function getTreeNode3($list, $root = 0, $pk='id', $pid = 'pid', $child = '_child') { // 创建根节点$root_tree = array();// 创建子节点$node_tree = array();// 迷路节点$no_tree = array();if(is_array($list)) { //既然不能使用数组函数改变源数据的下标，那么就把子节点的下标放在子节点tree即可foreach ($list as $key => $data) { // 判断是否存在parent$parentId = $data[$pid]; $nowId = $data[$pk];//根据$root 值 确定根节点数组,非 0 root 有问题if ($root == $parentId && $root == 0) { $node_tree[$nowId] = $data;$root_tree[$nowId] = &$node_tree[$nowId];}else if ($root == $nowId && $root != 0) { $node_tree[$nowId] = $data;$root_tree[$nowId] = &$node_tree[$nowId];if(isset($no_tree[$nowId])) { $node_tree[$nowId][$child] = &$no_tree[$nowId];}}else {

//同时确认 根节点 与 子节点是否都存在            //先找子节点            //$flag_node_tree = false;            //同时存在根节点，则映射父节点 与 子节点关联            if (isset($root_tree[$parentId]) && isset($node_tree[$parentId])) {                //同时存在 映射父子关系，改变子                $root_tree[$parentId] = &$node_tree[$parentId];                $node_tree[$nowId] = $data;                $node_tree[$parentId][$child][$nowId] = &$node_tree[$nowId];                if(isset($no_tree[$nowId])) {                    $node_tree[$nowId][$child] = &$no_tree[$nowId];                }            }else if (!isset($root_tree[$parentId]) && isset($node_tree[$parentId])) {                //父不存在子存在则写入子的子                $node_tree[$nowId] = $data;                $node_tree[$parentId][$child][$nowId] = &$node_tree[$nowId];                if(isset($no_tree[$nowId])) {                    $node_tree[$nowId][$child] = &$no_tree[$nowId];                }            }else if (isset($root_tree[$parentId]) && !isset($node_tree[$parentId])) {                //父节点存在，而子节点没有                $node_tree[$nowId] = $data;                $root_tree[$parentId][$child][$nowId] = &$node_tree[$nowId];                if(isset($no_tree[$nowId])) {                    $root_tree[$parentId][$child] = &$no_tree[$nowId];                }            }else {                $node_tree[$nowId] = $data;                $no_tree[$parentId][$nowId] = &$node_tree[$nowId];            }        }        /*echo "\nroot_tree\n";        print_r($root_tree);        echo "\nnode_tree\n";        print_r($node_tree);        echo "\nno_tree\n";        print_r($no_tree);*/    }}return $root_tree;

}

$treeval = getTreeNode3($nodesArrays,8);

print_r($treeval);