Hello,
I want to create a template sensor, which uses as state the state of another sensor with a specific attribute. Below is the source sensor, which should then be used for the template sensor. Problem is, that the entity name may change, but the attribute “id” stays the same.
So in short, I need to return the entity name and state of an entitiy, of which the attribute “id” equals 1354879.
Many thanks for your help!
{% set x = states.sensor | selectattr('attributes.id','equalto','1354879') | list | first %}
{{ x.entity_id }}
{{ x.state }}
Read to the bottom and I think I have supplied your solution -
How about looking at this in a different way. Note my example and then I reframe it into your used case at the end below. For instance I have a sensors that are actually a binary representing if there are one or more devices with a specific attribute - and then the attributes for that sensor are the sensors that currently have that attribute? I know it seems counterintuitive but it may be a way of backing into what you are looking for. Let me show you an example (and see the picture below):
In my configuration.yaml I have several sensors that show any Yolink or Shelly Sensors that are “Unkown” or “Unavailable”. I would suggest that you can have a trigger based upon the attributes of any similar sensors - for “Closed”, “Open”, “On”, “Off” etc. (or having that entity_id - see where I am going with this)?:
Note the picture and then my statement at the bottom:
template:
#
# This binary sensor not only specifies if any entities in the integration are unavailable, but also if
# there are any unavailable, it will contain an attribute that is a list of the entities that are unavailable.
#
- binary_sensor:
- name: "Any Yolink Unavailable"
state: "{{ integration_entities('yolink') | select('is_state', 'unavailable') | list | count > 0 }}"
attributes:
entity_id: "{{ integration_entities('yolink') | select('is_state', 'unavailable') | list }}"
unique_id: any_yolink_unavailable
#
# This binary sensor not only specifies if any entities in the integration are known, but also if
# there are any unknown, it will contain an attribute that is a list of the entities that are unknown.
#
- binary_sensor:
- name: "Any Yolink Unknown"
state: "{{ integration_entities('yolink') | select('is_state', 'unknown') | list | count > 0 }}"
attributes:
entity_id: "{{ integration_entities('yolink') | select('is_state', 'unknown') | list }}"
unique_id: any_yolink_unknown
#
# This binary sensor not only specifies if any entities in the integration are unavailable, but also if
# there are any unavailable, it will contain an attribute that is a list of the entities that are unavailable.
#
- binary_sensor:
- name: "Any Shelly Unavailable"
state: "{{ integration_entities('shelly') | select('is_state', 'unavailable') | list | count > 0 }}"
attributes:
entity_id: "{{ integration_entities('shelly') | select('is_state', 'unavailable') | list }}"
unique_id: any_shelly_unavailable
#
# This binary sensor not only specifies if any entities in the integration are known, but also if
# there are any unknown, it will contain an attribute that is a list of the entities that are unknown.
#
- binary_sensor:
- name: "Any Shelly Unknown"
state: "{{ integration_entities('shelly') | select('is_state', 'unknown') | list | count > 0 }}"
attributes:
entity_id: "{{ integration_entities('shelly') | select('is_state', 'unknown') | list }}"
unique_id: any_shelly_unknown
Note the one that is “true”:
So here are it’s attributes:
Alot of time I don’t care if something is unkown or unavailable, or expect it to be (such as a sensor that I cannot see because a smart plug controlling it is turned off on purpose), but this is good for checking the overall health of your system - especially if you occassionally have connectivity issues.
So for your use case - how about a sensor that represents the names of any entities which have the specific entity ID you are looking for? Then the attribute would have the name - and instead of binary it could just be text - and actually the state (text) could have the actual name to make it even easier to reference in code later - ?
Hi,
many thanks for your reply.
Unfortunately I am not getting it to work 
No first item, sequence was empty.
Wow you answer quickly! I have edited my post - reread it - ? And to test it on the fly, put the code for your sensor into the developer → templates window to play with it until it works
Oh, I see now that the id attribute is a number and not a string. Try without the quotes around the id number, as shown below. If that doesn’t work, confirm that there is some entity with that attribute and value in your system.
{% set x = states.sensor | selectattr('attributes.id','equalto',1354879) | list | first %}
{{ x.entity_id }}
{{ x.state }}
many thanks, it works great now! 
Sorry, I replied to the other answer by atlflyer, seems your and his answer overlapped As the solution of atlflyer works already, I think it’s not necessary anymore to try your approach too. But your answer is highly appreciated, thank you!