is_a
Filter a list of resource ids on category, or test if a single resource id belongs to a category.
This filter can be applied to a list of resource ids or a single resource id.
When it is applied to a list then it will filter the list of ids. Only those resource ids that belong to a certain category remain. Optionally the filter only returns the first n matches.
When applied to a single integer (resource id), then it will return a boolean. True when the id belongs to the parameter’s category, false otherwise.
Apply to a single resource id
Example:
{{ 1|is_a:"person"|yesno }}
Will output “yes”, because the resource with id 1 is a person (the System Administrator).
Apply to a list of resource ids
When applied to a list of ids:
{% for part_id in m.rsc[id].o.haspart|is_a:"person" %}
{{ m.rsc[part_id].title }}
{% endfor %}
This will list all collection members that are a person. While:
{% for part_id in m.rsc[id].o.haspart|is_a:"person":3 %}
{{ m.rsc[part_id].title }}
{% endfor %}
Lists only the first three collection members that are a person.