无限极分类 递归和迭代源码

<?php

header('content-type:text/html;charset=utf-8');

 $list=Array (  Array ( 'id' => 1 ,'name' => 'A' ,'pid' => 0 ) , Array ( 'id' => 2 ,'name' => 'B' ,'pid' => 0 ) , Array ( 'id' => 3 ,'name' => 'C' ,'pid' => 1 ), Array ( 'id' => 4 ,'name' => 'D' ,'pid' => 1 ) , Array ( 'id' => 5 ,'name' => 'E' ,'pid' => 2 )
, Array ( 'id' => 6 ,'name' => 'F' ,'pid' => 2 ) , Array ( 'id' => 7 ,'name' => 'G' ,'pid' => 3 ) , Array ( 'id' => 8 ,'name' => 'H' ,'pid' => 3 ) , Array ( 'id' => 9 ,'name' => 'I' ,'pid' => 3 ) , Array ( 'id' => 10 ,'name' => 'J' ,'pid' => 4 ) , Array (
'id' => 11 ,'name' => 'K' ,'pid' => 4 ), Array ( 'id' => 12 ,'name' => 'L' ,'pid' => 4 ) , Array ( 'id' => 13 ,'name' => 'M' ,'pid' => 5 ) , Array ( 'id' => 14 ,'name' => 'N' ,'pid' => 5 ) , Array ( 'id' => 15 ,'name' => 'O' ,'pid' => 5 ) , Array ( 'id' =>
16 ,'name' => 'P' ,'pid' => 6 ) , Array ( 'id' => 17 ,'name' => 'Q' ,'pid' => 6 ) , Array ( 'id' => 18 ,'name' => 'R' ,'pid' => 6 ) , Array ( 'id' => 19 ,'name' => 'S' ,'pid' => 6 ) , Array ( 'id' => 20 ,'name' => 'T' ,'pid' => 0 ) , Array ( 'id' => 21 ,'name'
=> 'U' ,'pid' => 20 ) , Array ( 'id' => 22 ,'name' => 'V' ,'pid' => 20 ) , Array ( 'id' => 23 ,'name' => 'W' ,'pid' => 21 ) , Array ( 'id' => 24 ,'name' => 'X' ,'pid' => 21 ) , Array ( 'id' => 25 ,'name' => 'Y' ,'pid' => 22 ) , Array ( 'id' => 26 ,'name' =>
'Z' ,'pid' => 22 ) );

echo "递归<br>";

 function getTree($list,$parent,$level=0)

 {

     $tree=array();

    foreach ($list as  $value) {

        if ($value['pid']==$parent) {

            $value['level']=$level;

            $tree[]=$value;

            $tree=array_merge($tree,getTree($list,$value['id'],$level+1));

        }

    }

     return $tree;

 }

$data=getTree($list,0);

foreach ($data as $key => $value) {

    echo str_repeat("——",$value['level']),$value['name'],'<br>';

}

echo "<hr>","迭代";

function iterate($list,$parent)

{

    $tree=array();

    while ($parent>0) {

        foreach ($list as $key => $value) {

            if ($value['id']==$parent) {

                $tree[]=$value;

                $parent=$value['pid'];

                break;

            }

        }

        

    }

    return $tree;

}

var_dump(iterate($list,26));

 ?>