Symfony2 - checking if file exists

Question

I have a loop in Twig template, which returns multiple values. Most important - an ID of my entry. When I didn\'t use any framework nor template engine, I used simply

Answer 1

Just add a little comment to the contribution of Sybio:

The Twig_Function_Function class is deprecated since version 1.12 and will be removed in 2.0. Use Twig_SimpleFunction instead.

We must change the class Twig_Function_Function by Twig_SimpleFunction:

 new \Twig_Function_Function('file_exists'), // Old class
            'file_exists' => new \Twig_SimpleFunction('file_exists', 'file_exists'), // New class
        );
    }

    public function getName()
    {
        return 'twig_extension';
    }
}

The rest of code still works exactly as said Sybio.