Remove items by attribute test: rejectattr

The rejectattr filter is the opposite of selectattr. It iterates over a list of objects and removes those where a specified attribute passes the given test, keeping only those that fail it.

This is useful when you want to exclude 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] based on an attribute rather than select them. For example, you might want to remove all unavailable entities from a list, exclude entities that are off, or filter out sensors with a specific device class. It provides a cleaner, more readable alternative to writing selectattr with a negated condition.

Usage

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

{{ expand("light.home_lights")
  | rejectattr("state", "eq", "off")
  | map(attribute="entity_id")
  | list
}}

["light.kitchen", "light.living_room"]

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

rejectattr(
    value: list,
    attribute: str,
    *args: str,
) -> iterable

Function parameters

The following parameters can be provided to this filter.

Reject by truthiness

When no test is specified, items are removed if the attribute value is truthy.

{{
  expand("light.home_lights")
  | rejectattr("attributes.brightness")
  | map(attribute="entity_id")
  | list
}}

["light.hall", "light.porch"]

Good to know

• Returns an iterable, not a list. Add | list before using it with length, first, or looping twice.
• Without a test, items are removed when the attribute is truthy.
• Numeric comparisons against state strings compare alphabetically unless you convert first. "9" is greater than "10" as strings.

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.

Exclude unavailable entities

Remove entities that are unavailable or unknown before processing.

{{
  expand("sensor.home_sensors")
  | rejectattr("state", "in", ["unavailable", "unknown"])
  | map(attribute="entity_id")
  | list
}}

["sensor.temperature", "sensor.humidity", "sensor.pressure"]

Remove entities that are off

Keep only entities that are not in the “off” state.

{{
  expand("light.home_lights")
  | rejectattr("state", "eq", "off")
  | map(attribute="name")
  | join(", ")
}}

Kitchen light, Living room light

Exclude a specific device class

Remove sensors of a particular device class from a collection.

{{
  expand("sensor.home_sensors")
  | rejectattr("attributes.device_class", "eq", "battery")
  | map(attribute="entity_id")
  | list
}}

["sensor.temperature", "sensor.humidity", "sensor.pressure"]

Chain rejectattr with selectattr

Combine both filters to precisely control which entities are included.

{{
  expand("sensor.home_sensors")
  | rejectattr("state", "in", ["unavailable", "unknown"])
  | selectattr("attributes.device_class", "eq", "temperature")
  | map(attribute="state")
  | map("float")
  | average
  | round(1)
}}

21.2

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:

• Filter items by attribute test: selectattr - Filters a list, keeping only items where a specified attribute passes a test.

• Remove items by test: reject - Filters a list, removing items that pass a given test. The opposite of select.

• Filter items by test: select - Filters a list, keeping only items that pass a given test.

• Transform list items: map - Applies a filter to each item or extracts an attribute from each item in a list.

• Expand groups into entities: expand - Expands groups and zones into a list of individual entity state objects.