This is extremely useful for outputting subsets of querysets in a Django template. For example, if you only want to show the first three results of your queryset and hide the rest under a “Show More” link, you use two loops with slicing:

<ol>
  {% for color in widget.colors|slice:':3' %}
    <li>{{ color }}</li>
  {% endfor %}

  {% for color in widget.colors|slice:'3:' %}
    <li class="collapse class-event-collapse">{{ color }}</li>
  {% endfor %}
</ol>
<button data-toggle="collapse" data-target=".class-event-collapse" class="class-event-dates">See More Colors</button>