The yesno filter maps values that evaluate to True, False, and None to "yes", "no", and "maybe" or to alternative strings passed in as a comma-delimited string.

Variable

inventory = {
    'gloves': 0,
    'hats': 51,
    'scarves': 2,
    'socks': 13
}

Template

<ol>
{% for item, remaining in inventory.items %}
  <li class="{{ remaining|yesno:'instock,outofstock' }}">
    {{ item }}: {{ remaining }} remaining
    {{ remaining|yesno:',(time to place an order)' }}
  </li>
{% endfor %}
</ol>

Notice how the yesno filter is used once to determine the class value and again to determine whether or not to output “(time to place an order)”.

Result

<ol>
<li class="outofstock">gloves: 0 remaining (time to place an order)</li>
<li class="instock">hats: 51 remaining</li>
<li class="instock">scarves: 2 remaining</li>
<li class="instock">socks: 13 remaining</li>
</ol>