使用PHP动态创建变量

I'm working on a REST styled API, and I want to be able to break the URL down into individual variables.

Say I have the following URL: www.example.com/user/post/1

I'd like to make the following variables:

$uri_1 = user
$uri_2 = post
$uri_3 = 1

I tried to do this but it got stuck in a loop

 $path = explode('/', $this->path($uri));
 for($i=0;$i < count($path);$i++){
       $uri_.$i = $path[i];
 }

$url = explode('/', strtolower(trim($_SERVER['REQUEST_URI'], '/')));

$uri_1 = isset($url[0])?$url[0]:'';
$uri_2 = isset($url[1])?$url[1]:'';
$uri_3 = isset($url[2])?$url[2]:'';

Here's how you do it for an arbitrary number of variables, using PHP's variable variables feature:

 $path = explode('/', $this->path($uri));
 for($i=0;$i < count($path);$i++){
       ${"uri_".$i} = $path[i];
 }