How to check if entry field value is already outputted, and prevent it again? For an event page I have the option to filter on cities and countries. Each event has entry fields in which the city and country, of which the values are outputted in a drop down list on the front end.

As some events happen in the same country and city I have multipe values that are the same. Is there any chance to filter these values in Craft and output it only ones?

{% for entry in craft.entries.section('events') %}                      
    &lt;option value="{{entry.stad}}" name="{{ entry.stad }}"&gt;{{ entry.stad }}&lt;/option&gt;
{% endfor %}
Craft has a group filter, that does just that:

{% for stad, events in craft.entries.section('events') | group('stad') %}
    &lt;option value="{{ stad }}"&gt;{{ stad }}&lt;/option&gt;
{% endfor %}