小数范围与小数

I'm trying to add a class "semi" to a star rating system I'm making with Twig. I can't create custom functions so it need to be done "frontend".

What I tried is this:

 {% for i in range(0, 5, 0.5) | limit(5) %} {# limit to 5 stars #}
  {% set starClass = (productScore >= i ? "on" : "off")  %}
   <span class="star fa fa-star {{ starClass }}"></span>
 {% endfor %}

When productScore equals 3 I get a result like:

 <span class="star fa fa-star on"></span>
 <span class="star fa fa-star on"></span>
 <span class="star fa fa-star on"></span>
 <span class="star fa fa-star off"></span>
 <span class="star fa fa-star off"></span>

But how can I create a function that also add a classname semi when productScore equals 3.5??

 <span class="star fa fa-star on"></span>
 <span class="star fa fa-star on"></span>
 <span class="star fa fa-star on"></span>
 <span class="star fa fa-star semi"></span>
 <span class="star fa fa-star off"></span>

Somebody have any idea?

I would go with something like this

{% set productScore = 3.5 %}
{% for i in range(0, 4) %}
    {% set starClass = productScore - i >= 1 ? 'on' : (productScore - i >= 0.5 ? 'semi' : 'off') %}
    <span class="star fa fa-star {{ starClass }}"></span>
{% endfor %}

demo