php无限分类(递归版本)

<?php
$rows = array(
    array(
        'id' => 1,
        'name' => 'dev',
        'parentid' => 0
    ),
    array(
        'id' => 2,
        'name' => 'php',
        'parentid' => 1
    ),
    array(
        'id' => 3,
        'name' => 'smarty',
        'parentid' => 2
    ),
    array(
        'id' => 4,
        'name' => 'life',
        'parentid' => 0
    ),
    array(
        'id' => 5,
        'name' => 'pdo',
        'parentid' => 2
    ),
    array(
        'id' => 6,
        'name' => 'pdo-mysql',
        'parentid' => 5
    ),
    array(
        'id' => 7,
        'name' => 'java',
        'parentid' => 1
    )
);

// 72648
// 84072

function findChild(&$arr,$id){
  
    $childs=array();
     foreach ($arr as $k => $v){
         if($v['parentid']== $id){
              $childs[]=$v;
		 
         }
        
    }
      
    return $childs;
    
    
}
function build_tree($root_id){
    global $rows;
    $childs=findChild($rows,$root_id);
    if(empty($childs)){
        return null;
    }
   foreach ($childs as $k => $v){
       $rescurTree=build_tree($v[id]);
       if( null !=   $rescurTree){ 
       $childs[$k]['childs']=$rescurTree;
       }
   }
    return $childs;
}

 
$tree=build_tree(0);

echo memory_get_usage();

print_r($tree);



?>