Expand groups into entities: expand

The expand template function takes groupsGroups are a way to organize your entities into a single unit. [Learn more], zonesZones allow you to specify certain regions on a map. They enable zone presence-detection and can be used in automations. For example, to start the vacuum after you left home or start the heating at home when you leave the office. [Learn more], or lists of entity IDs and expands them into a flat list of individual entityAn entity represents a sensor, actor, or function in Home Assistant. Entities are used to monitor physical properties or to control other entities. An entity is usually part of a device or a service. [Learn more] state objects. If you pass in a group, it gives you all the individual entities that belong to that group, with duplicates removed.

This is extremely useful when you want to work with a collection of entities. For example, you might have a group of temperature sensorsSensors return information about a thing, for instance the level of water in a tank. [Learn more] and want to calculate the average, find the highest reading, or count how many are above a threshold. The result contains full state objects, so you can access .state, .entity_id, .attributes, and .last_changed on each one.

Usage

Here’s how to use this template function. Copy any example and adjust it to your setup.

{{ expand("light.living_room_lights") | map(attribute="entity_id") | list }}

[
  "light.living_room_ceiling",
  "light.living_room_lamp",
  "light.living_room_strip",
]

{{ "light.living_room_lights" | expand | map(attribute="entity_id") | list }}

[
  "light.living_room_ceiling",
  "light.living_room_lamp",
  "light.living_room_strip",
]

Function signature

The signature is a technical summary of this template function. It shows the name of the function, the values (called parameters) it accepts, and what type of data each parameter expects (for example, a piece of text or a number).

Function parameters that have a = with a value after them are optional. If you leave them out, the default value shown is used automatically.

Function parameters without a = are usually required. A few optional parameters have no default value, so the signature shows them without a = as well. To check whether a parameter is required, look at the parameter list below the signature. Each parameter is marked as Required or Optional.

The most common optional parameter without a default value is default. The default parameter sets the value a function returns when the function can’t produce a result, for example, when float gets text that isn’t a number. If you leave out default, there is no fallback value, so most functions raise an error and the template fails. The parameter list of each function says what happens. If you set default, the function returns your value instead.

round(
    value: Any,
    precision: int = 0,
    method: str = "common",
    default: Any,
) -> float | int | Any

expand(
    *args: str | State | list,
) -> list[State]

Function parameters

The following parameters can be provided to this function.

Good to know

• Returns full state objects, not entity IDs. Add | map(attribute="entity_id") to get IDs.
• Entities that do not exist are silently dropped from the result.
• The result has duplicates removed, but it isn’t sorted. To sort it by entity ID, add | sort(attribute="entity_id").
• The group itself isn’t part of the result, only its members. This also applies to groups that you create with the Group integration, such as a light group.
• A zone expands to the persons in that zone.
• Nested groups are expanded recursively, so you get every individual entity in the end.

Try it yourself

Ready to test this? Open Settings > Tools > Template, paste the example into the Template editor, and watch the result update on the right. Edit the values to see how the function adapts to your own entitiesAn entity represents a sensor, actor, or function in Home Assistant. Entities are used to monitor physical properties or to control other entities. An entity is usually part of a device or a service. [Learn more].

More examples

Real scenarios where this function comes up in automations and templates. Copy any example and adapt it to your setup.

Count how many lights are on in a group

{{
  expand("light.home_lights")
  | selectattr("state", "eq", "on")
  | list
  | count
}}

5

Calculate average temperature from a group

Combine expand with average to get the mean temperature across a group of sensors.

{{
  expand("sensor.temperature_sensors")
  | map(attribute="state")
  | map("float")
  | average
}}

21.3

Find the entity with the highest value

States are text, so sorting the states from high to low puts "9" above "21". To sort by value, this example pairs each value, as a number, with its entity ID. It then sorts the pairs from high to low and picks the first one. Sensors without a number, such as unavailable ones, are left out. If no sensor has a number, the template returns nothing.

{% set sensors = expand("sensor.temperature_sensors")
  | selectattr("state", "is_number") | list %}
{% if sensors %}
{{
  zip(
    sensors | map(attribute="state") | map("float"),
    sensors | map(attribute="entity_id")
  )
  | sort(reverse=true)
  | first
  | last
}}
{% endif %}

sensor.kitchen_temperature

Still stuck?

The Home Assistant community is quick to help: join Discord for real-time chat, post on the community forum with your template and expected result, or share on our subreddit /r/homeassistant.

Related template functions

These functions work well alongside this one:

• Get entity state: states - Returns the state value of an entity, or lets you iterate over all entity states.

• Test entity state: is_state - Tests if an entity is in a specific state.

• Get entities in an area: area_entities - Returns a list of entity IDs associated with a given area.