无极分类之子孙树、父辈树

<?php
    function subTree($arr, $id=0, $depth=0)
    {
        static $tree = array();
        foreach ($arr as  $key=>$value) {
            if($value[‘father_id‘] == $id)
            {
                $value[‘depth‘] = $depth;
                $tree[] = $value;
                subTree($arr, $value[‘id‘], $depth+1);
                //tree($arr, $value[‘id‘],$depth+1);
            }
        }
        return $tree;
    }  

function fatherTree($arr,$id) {
        static $list = array();
        foreach($arr as $v) {
            if($v[‘id‘] == $id) {
                fatherTree($arr,$v[‘father_id‘]);
                $list[] = $v;
            }
        }  

        return $list;
    }  

 $arr = [
	[‘id‘=>1,‘name‘=>‘news‘,‘father_id‘=>0],
	[‘id‘=>2,‘name‘=>‘article‘,‘father_id‘=>0],
	[‘id‘=>3,‘name‘=>‘local news‘,‘father_id‘=>1],
	[‘id‘=>4,‘name‘=>‘good article‘,‘father_id‘=>2],
	[‘id‘=>5,‘name‘=>‘bad article‘,‘father_id‘=>2],
	[‘id‘=>6,‘name‘=>‘sea‘,‘father_id‘=>4],
];

$tree = subTree($arr);
foreach($tree as $v){
	echo str_repeat(‘----‘,$v[‘depth‘]).$v[‘name‘].$v[‘depth‘].‘<br>‘;
}

$list = fatherTree($arr,6); 

foreach ($list as $key => $value) {
	echo $value[‘name‘].‘>>‘;
}