Setting element of array from Twig

Question

How can I set member of an already existing array from Twig?

I tried doing it next way:

{% set arr[\'element\'] = \'value\' %}

but

Answer 1

I've found this issue very annoying, and my solution is perhaps orthodox and not inline with the Twig philosophy, but I developed the following:

$function = new Twig_Function('set_element', function ($data, $key, $value) {
    // Assign value to $data[$key]
    if (!is_array($data)) {
        return $data;
    }
    $data[$key] = $value;
    return $data;
});
$twig->addFunction($function);

that can be used as follows:

{% set arr = set_element(arr, 'element', 'value') %}