Remove items by test: reject

The reject filter is the opposite of select. It iterates over a list and removes items that pass the given test, keeping only those that fail it.

This is useful when it is easier to describe what you want to exclude rather than what you want to keep. For example, you might want to remove all zero values from a list, exclude unavailable states, or filter out empty strings. Instead of writing a complex select with a negated condition, reject lets you express the exclusion directly and clearly.

Usage

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

{{ [1, 2, 3, 4, 5] | reject("greaterthan", 3) | list }}

[1, 2, 3]

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

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

Function parameters

The following parameters can be provided to this filter.

Reject by truthiness

When no test is specified, reject removes items that are truthy, keeping only falsy values.

{{ [0, 1, "", "hello", none, true] | reject | list }}

[0, '', None]

Exclude specific values

{{
  ["on", "off", "unavailable", "on", "unknown"]
  | reject("equalto", "unavailable") | list
}}

['on', 'off', 'on', 'unknown']

Good to know

• Returns an iterable, not a list. Add | list before using it with length, first, or looping twice.
• Without a test, truthy items are removed. Zero, empty strings, and None are kept because they are falsy.

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.

Remove zero values before averaging

Exclude zero readings that might skew an average calculation.

{{
  [21.5, 0, 19.8, 22.3, 0]
  | reject("equalto", 0)
  | list
  | average
  | round(1)
}}

21.2

Exclude non-numeric values

Remove values that are not valid numbers before performing calculations.

{{
  expand("sensor.temperature_sensors")
  | map(attribute="state")
  | reject("in", ["unavailable", "unknown"])
  | map("float")
  | list
}}

[21.5, 19.8, 22.3]

Remove empty strings

Clean up a list by removing empty or blank entries.

{% set items = ["kitchen", "", "bedroom", "", "hall"] %}
{{ items | reject("equalto", "") | list }}

["kitchen", "bedroom", "hall"]

Exclude outlier values

Remove temperature readings that are outside a reasonable range.

{{
  [21.5, 19.8, -40.0, 22.3, 99.9]
  | reject("greaterthan", 50)
  | reject("lessthan", -20)
  | list
}}

[21.5, 19.8, 22.3]

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

• Remove items by attribute test: rejectattr - Filters a list, removing items where a specified attribute passes a test. The opposite of selectattr.

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

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