Templating: how to find all possibilities within home assistant?

Configuration Frontend
1

I understand (basic) templating but I wonder: how nd where do I find out all possibilities?

An example:


Automations
    - alias: Battery low notification
      id: "ag2i86995uix9vt84a6g7699h"
      trigger:
        - platform: time
          at: "20:00:00"
      mode: single
      max_exceeded: silent
      condition:
        - condition: template
          value_template: >
            {{ (states.sensor 
              | selectattr('attributes.device_class', 'eq','battery')
              | selectattr('attributes.unit_of_measurement', 'eq', '%') 
              |rejectattr('state','in','[unavailable,unknown]')
              | map(attribute='state') | map('int')
              |select('<=',5) |list|length)>0 }}           
      action:
        - delay: "00:30:00"
        - service: notify.telegram_vm
          data:
            title: "{{ '\U0001F50B' }} *Low Battery*"
            message: >
              {% set batteries = states.sensor 
                | selectattr('entity_id', 'has_value') 
                |rejectattr('state','in','unavailable,unknown')
                | selectattr('attributes.device_class', '==', 'battery') 
                | selectattr('attributes.unit_of_measurement', '==', '%') | list %}
              {% set low_battery = batteries | map(attribute='state') | map('int') | select('<=', 5) | map('string') | list %}
              {{ batteries | selectattr('state', 'in', low_battery) | map(attribute='name') | list | join('\n') }}

I found this automation from someone. I can read what it does. I am curious to find all the possibilities of the selectattr and rejectattr filters; all those attributes side from device_class or unit_of_ measuring.

2

I don’t know that there is a single source that lists “all possibilities”.

You can find a number of tests in the Jinja Template Builder docs, but Home Assistant also includes some custom tests and functions which can be found in the Templating docs.

3

I found the tests and functions in the documentation. I was pointing to the things like attributes.device_class, attribute=‘state’, etc.

I somehow can’t seem to wrap my head around all possibilities to select or filter within home assistant devices/entities.
So, on a ELI5-level, is there a list of items I can ask in the first portion, second and third portion of the line below.
selectattr('first', 'second', 'third')

I’ve seen for second, eq (equal), but also search and match. And can I use ‘==’? It seems that there are more roads leading to Rome with jinja templating.

4

The possibilities are endless. There is no way to “find all possibilities” or for anyone to explain them. The only limitations are your imagination and programming skills.

5

I understand, but I don’t. To get things from home assistant, there is a limit right?!

attributes.device_class and attributes.unit_of_measurement are two, but attributes.idontknowwhatimdoing wont return anything…

6 
attributes.device_class

device_class is the name of one of the entity’s attributes, if the entity has it.

Go to Developer Tools → States, select an entity, and its attributes will be displayed at the top of the page.

If you are using a browser on a PC, the list of entities displays a third column showing each entity’s attributes (the same list on a phone’s narrow screen doesn’t display the third column).

7

The first argument is like an address for the attribute/key
that is of interest. That can be either the name of one of the properties of the state object like entity_id or a sub-property like attributes.device_class.

The second argument is the test. I linked those previously. Be aware that some tests can be expressed multiple ways such as:

  • eq, ==
  • gt, >
  • le, <=
  • ne, !=

Not all uses of selectattr() will require a third argument, this is based on the type of test being used. Test that are comparisons usually require a third argument as the comparand.

As Taras noted above, you can find an entity’s available attributes in the Dev Tool > States tab. You can also list them using the state object method in the Template editor:

To print the state object with its list of properties:
{{ states.sensor.example }}

To list the subcomponents of the property "attributes":
{{ states.sensor.example.attributes }}

Though the above explanation focuses on using selectattr() with state objects, it can be used with user-created dictionaries as well.