Hi. I have a form which looks like this:

Lottery | Low pay | High pay | Choice
   1    | 28      | 28       | [ ] 
   2    | 24      | 36       | [ ] 
   3    | 20      | 40       | [x] 
   4    | 16      | 50       | [ ] 
   
Basically each lottery is an option for a IntegerField, but I need to render not just a label, but a whole row. Assuming I have a list of the form
Lotteries [
[1, 28, 28],
[2, 24...
]
I would render this in the template like this:
<tbody>
    {{ for choice in form.lotteries }}
        <tr>
            <td class="text-center">Lottery {{C.Lotteries.{{forloop.counter0}}.0}}</td>
            <td class="text-center">{{ C.Lotteries.{{forloop.counter0}}.1 }}</td>
            <td class="text-center">{{ C.Lotteries.{{forloop.counter0}}.2 }}</td>
            <td class="text-center">{{ choice }}</td>
        </tr>
    {{ endfor }}
</tbody>

Of course this won't work as you can't use forloop.counter just like that. But then, I don't know how I should tackle this issue: I can't just use choice labels because otree will escape any HTML I try to put in them. What should be the correct approach?

The template language does not support doing that.

I recommend generating the raw HTML in vars_for_template, where you can use regular Python constructs like zip(), array indexing, etc.

Also take a look at the 'persist-raw' in otree-snippets, which will preserve the state of the radio buttons if the page gets reloaded.

So, I pass to the template a variable which, among other, contains this fstring:

f"""<td class="text-center">{{{{ form.lottery.{i} }}}}</td>"""

The renderer then complains it cannot resolve form.lottery.0 
I suspect the vars_for_template are evaluated before form_fields, so this approach would not work

for the record, the HTML generated by my vars_for_template is identical to hardcoded HTML which works, so it's not an error on how to reference formfield choices or things like that

Nevermind, I indeed had an issue in how I had defined the options. Still, this approach does not work for me because variables are printed as is:

Lottery | Low pay | High pay | Choice
   1    | 28      | 28       | {{ form.lottery.0 }}
   2    | 24      | 36       | {{ form.lottery.1 }}
   3    | 20      | 40       | {{ form.lottery.2 }}
   4    | 16      | 50       | {{ form.lottery.3 }}
   
 etc

Don't generate any {{}} characters. Just generate the whole table in vars_for_template, with the raw HTML code for the radio buttons, e.g. <input type="radio" name=...>