Intersection of two lists in jinja templates for condition?

Configuration
1

How to intersect two lists in HA jinja templates? The goal is to return single boolean value, so it can be used in conditions.

Example:

{% set my_test_json = {
  "list1": ["a1", "a2", "b1", "b2"],
  "list2": ["a2", "b2", "c2", "d2"]
} %}

How to return true if there are common elements between list1 and list2 or false otherwise?

Thanks!

2

You only need to loop one of the lists.


{% set ns = namespace(bool=false) %}

{% for val in my_test_json.list1 %}
  {% if val in my_test_json.list2 %}
    {% set ns.bool = true %}
  {% endif %}
{% endfor %}

{{ ns.bool }}
1 Like
3

That’s a working solution, thanks!

Would be nice to have some basic list/set operations available for HA template engine.

4 
{{ (list1 + list2) | count != dict.fromkeys(list1 + list2) | count }}

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NOTE

This works only if there are no duplicate values within a list. For example, list1 cannot have more than one instance of a2. If it does then the suggested template will produce an incorrect result. If there’s a possibility that either list can contain duplicates within it then use the example Hellis81 provided.

1 Like