Dynamic creation of class object when using namespace?

Question

PHP

Good afternoon!
The router has a method:

public function Run()
    {
        $uri = $this -> getURI();

        foreach ($this -> routes as $uriPattern => $path) {
           if (preg_match("~$uriPattern~", $uri))
           {
               $rout = explode('/', $path);
            //    print_r($rout);
               $controllerName = array_shift($rout) . 'Controller';
               $actionName = array_shift($rout);
               
               $controllerFile = ROOT . "/controllers/{$controllerName}.php";

               if (file_exists($controllerFile)) {
                    include_once($controllerFile);                    
               }

               $controllerObject = new Controllers\installAppController;
               /*
               * нужно вот так как то:
               * $controllerObject = new Controllers\$controllerName;
               */
               $result = $controllerObject -> $actionName();
               if ($result !== null) {
                   break;
               }
           }
        }
    }

How can I form a class name based on ?
use Calculation\Margin\Controllers;

Whole file

<?php

namespace Calculation\Margin\Components\Router;

require_once ROOT.'/config/routes.php';
use Calculation\Margin\Config\RoutesList;

use Calculation\Margin\Controllers;


class Router
{
    
    private $routes;

    public function __construct ()
    {

        $this -> routes = RoutesList::getRoutes();

    }

    private function getURI(): string
    {
        if (!empty($_SERVER['REQUEST_URI'])) {

             return trim($_SERVER['REQUEST_URI'], '/');
        }
    }
    
    public function Run()
    {
        $uri = $this -> getURI();

        foreach ($this -> routes as $uriPattern => $path) {
           if (preg_match("~$uriPattern~", $uri))
           {
               $rout = explode('/', $path);
            //    print_r($rout);
               $controllerName = array_shift($rout) . 'Controller';
               $actionName = array_shift($rout);
               
               $controllerFile = ROOT . "/controllers/{$controllerName}.php";

               if (file_exists($controllerFile)) {
                    include_once($controllerFile);                    
               }

               $controllerObject = new Controllers\installAppController;
               /*
               * нужно вот так как то:
               * $controllerObject = new Controllers\$controllerName;
               */
               $result = $controllerObject -> $actionName();
               if ($result !== null) {
                   break;
               }
           }
        }
    }
}

Answer 1

$className = '\\Calculation\\Margin\\Controllers\\'.$controllerName;
$controllerObject = new $className;