PHP Infinitus classification array _ PHP Tutorial

PHP Infinitus classification array. PHP Infinitus array? Php $ dataarray (1 array (id1, namename1, pid0), 2 array (id2, namename2, pid0), 3 array (id3, namename3, pid1 ), 4 array (id PHP Infinitus array

  array('id' => 1,'name' => 'name1','pid' => 0),            2 => array('id' => 2,'name' => 'name2','pid' => 0),            3 => array('id' => 3,'name' => 'name3','pid' => 1),            4 => array('id' => 4,'name' => 'name4','pid' => 0),            5 => array('id' => 5,'name' => 'name5','pid' => 3),            6 => array('id' => 6,'name' => 'name6','pid' => 3),    ); $str = getTree(0);$str = "" . $str . "";echo $str;function getTree($id,$spac=0){    $data = array( 1 => array('id' => 1,'name' => 'name1','pid' => 0),            2 => array('id' => 2,'name' => 'name2','pid' => 0),            3 => array('id' => 3,'name' => 'name3','pid' => 1),            4 => array('id' => 4,'name' => 'name4','pid' => 0),            5 => array('id' => 5,'name' => 'name5','pid' => 3),            6 => array('id' => 6,'name' => 'name6','pid' => 3),    );    $spac = $spac + 2;    static $str;         foreach ($data as $k => $v) {        if ($v['pid'] == $id) {            $arr[] = $v;            $str .= "" . str_repeat(" ",$spac) . "|--" . $v['name'] . "";            getTree($v['id'],$spac);         }     }         return $str;}   ?>

Why? Php $ data = array (1 = array (id = 1, name = name1, pid = 0), 2 = array (id = 2, name = name2, pid = 0 ), 3 = array (id = 3, name = name3, pid = 1), 4 = array (id...