for循环关联数组取重要值

$config = array('ddsd'=>13,'fdasfda'=>'fdasfsda','fdasf'=>'fdsafdsa')
$num = 0;
for ($i = 0;$i < count($config); $i++)
{
    $num += 1;
    echo key($config).'=>'.current($config).'//'.$num.'<br />';
    next($config);
}