动态子字段分配

I have some difficulties to explain my problem, some code is better than a long text:

<?php

$n = new stdClass();
$f = 'field[0][0]';
$n->$f = 1;
var_dump($n);

The current result:

object(stdClass)#1 (1) {
  ["field[0][0]"]=>
  int(1)
}

The desired result:

object(stdClass)#1 (1) {
  ["field"]=>
  array(1) {
    [0]=>
    array(1) {
      [0]=>
      int(1)
    }
  }
}

Is it possible?

Thank's in advance.

eval('$n->'.$f.'=1;');

additional to this,
please check $f is from TRUSTABLE source

How about using:

$n = new stdClass();
$f = 'field';
$n->$f = array(array(1));
var_dump($n);

$n = new stdClass();
$f = 'field';
$n->$f = array(array(1));
var_dump($n);

object(stdClass)#1 (1) { ["field"]=> array(1) { [0]=> array(1) { [0]=> int(1) } } }