Help with last changed template

1

Is there a way to write this:

states.switch.lounge_dehumidifier.last_changed

In this format (this is wrong):

state_attr('switch.lounge_dehumidifier', 'last_changed')
1 Like
2

I have played with this earlier and my feeling is the latter code you can use only for additional (i.e non-core) attributes of any state/object. And last_xxx, object_id etc are all part of the base Entity object and require a direct access to them.
Haven’t looked into the HA code yet, it should be obvious I presume.

Could you tell why the former is not suitable?

3

If the entity doesn’t exist the first will throw an error. The second just returns ‘unknown’.

4

That’s true. Is that the only issue you’d like to avoid?

5

Yes it is.

6

how about

states.switch.lounge_dehumidifier and states.switch.lounge_dehumidifier.last_changed

or

{% if states.switch.lounge_dehumidifier is not none %}
  {{ states.switch.lounge_dehumidifier.last_changed }}
{% endif %}

(as I don’t know anything about your context)?

Anyway, from reading this it’s obvious why the state_attr approach doesn’t work.
So basically if you want your template code to work, just check that the entity does exist and only then access its last_changed, that’s it.

And as it’s most likely Jinja2 template, after reading the Implementation section on Variables I’d use something like

{% set device = 'lounge_dehumidifier' %}
{% if states.switch[device] is defined %}
  {# it's safe to access the last_changed attribute #}
  {{ states.switch[device].last_changed }} 
{% endif %}

or

{% set device = 'lounge_dehumidifier' %}
{% if states.switch | attr(device) %}
  {# it's safe to access the last_changed attribute #}
  {{ states.switch[device].last_changed }} 
{% endif %}
7

I re-take this topic because documentation says:

Avoid using states.sensor.temperature.state, instead use states('sensor.temperature'). It is strongly advised to use the states(), is_state(), state_attr() and is_state_attr() as much as possible, to avoid errors and error message when the entity isn’t ready yet (e.g., during Home Assistant startup).

How can I write states.switch.luz_led_cocina.last_changed in the recommended format?

{{ state_attr('switch.luz_led_cocina', 'last_changed') }} doesn’t work

2 Likes
8

Last changed isn’t an attribute. It’s a property of the object. So in that case you have to use:

states.switch.luz_led_cocina.last_changed

Petro wrote a great post on this:

9

For anyone trying to do this in 2023: This is the only answer to getting last_changed into a template. I’ve been looking for 3 hours and this is the only way. Save yourself some time and ignore the documentation that says not to access entities like this.

5 Likes
10

The documentation only recommends accessing the state and attributes with specific functions, not object properties.

1 Like
11

Can you at least see how somewhat casual users can see that as a distinction without a difference? I realize there’s a lot of nuance here, and I wasn’t attacking you, I just want to help users like me who don’t have a double major in Jinja and Home Assistant.

Sorry if I came off wrong

Edit to add: understand what users in this thread are saying, and then we see these answers a year old. I’m simply updating the timestamp for people.

3 Likes