多层嵌套简单梳理

gistfile1.php

<?php
/**
 * 多层嵌套简单梳理
 */
$child_to_parent = array(
    1 => 0, 
    2 => 0, 
    3 => 1, 
    4 => 1, 
    5 => 3, 
    6 => 5, 
    7 => 2, 
    8 => 0, 
    9 => 4, 
);
$childs = array();
foreach ($child_to_parent as $c => $p) {
    $childs[$p][]=$c;
}
function getChild($data, $pid)
{
    $arr = array();
    foreach ($data[$pid] as $key => $value) {
        $arr[$value] = isset($data[$value]) ? getChild($data, $value) : 0;
    }
    return $arr;
}
$re = getChild($childs, 0);

print_r($childs);
print_r($re);