{% for o in [1,2,3] %}
    <div class="{% cycle 'row1' 'row2' %}">
        {% cycle 'row1' 'row2' %}
    </div>
{% endfor %}

Could not parse the remainder: '[1,2,3]' from '[1,2,3]'

{% for o in "123"|make_list %}
    <div class="{% cycle 'row1' 'row2' %}">
        {% cycle 'row1' 'row2' %}
    </div>
{% endfor %}

{% with '1 2 3' as list %}
  {% for i in list.split %}
    {{ i }}<br>
  {% endfor %}
{% endwith %}

1
2
3

<div class="btn-group">
  <a class="btn btn-primary dropdown-toggle" data-toggle="dropdown" href="#">
    Modality
    <span class="caret"></span>
  </a>
  <ul class="dropdown-menu" id="Modality">
    <li><a href="#">Action</a></li>
  </ul>
</div>

{% with 'Modality Otherbutton Thirdbutton' as list %}
  {% for i in list.split %}
    <!-- copy/paste above code with Modality replaced by {{ i }} -->
  {% endfor %}
{% endwith %}

{% for x in "1 2 3" %}