How to prefill select form field with twig

Question

How can I use Twig to prefill a select option in a form?

<select>
    <option value="6" {{person[0].age == '6' ? selected : ''}}>6</option>
</select>

I've tried the above to no avail.

Answer 1

I ended up doing something like this:

{% if person[0].age == '6' %}
     <option value="6" selected>6</option>
{% else %}
     <option value="6">6</option>
{% endif %}

It's just a lot more code than being able to do it like the example in my question.