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Remove duplicate values: unique

The unique filter removes duplicate values from a list, keeping only the first occurrence of each value. Unlike converting to a set, the unique filter preserves the original order of items. You can also deduplicate based on a specific attribute of each item.

This is useful when you have a list that may contain duplicates and you want to remove them while keeping the order intact. For example, you might collect states from multiple 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] and want to know the distinct states that exist, or you might merge multiple lists of devicesA device is a model representing a physical or logical unit that contains entities. and need to eliminate duplicates. The attribute parameter is especially helpful when working with lists of objects, letting you deduplicate by a specific property.

Usage

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

As a filter

{{ [1, 2, 2, 3, 1, 4] | unique | list }}

Result (list)

[1, 2, 3, 4]

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.

How to read a signature

Here is the signature of the round filter as an example:

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

round is the name of the function.
Between the parentheses are the parameters. Each parameter has a name, followed by a colon and the type of value the parameter expects. The type only tells you what kind of value to pass. For default: Any, you pass a value of any type, such as 0 or "unknown", not the word Any.
= 0 and = "common" are default values. You can leave out precision and method, and round uses these default values.
default has no =, but the parameter list marks default as optional. If you leave out default and round gets a value that isn’t a number, round raises an error.
-> shows the type of value the function returns.
Inside a signature, | means “or”. This function returns a decimal number, a whole number, or the value you passed as default.

round is a filter, so the first parameter, value, is the value before the |. For example, {{ 3.14159 | round(2) }} returns 3.14.

The types you’ll see most often:

str: text, such as "hello"
int: a whole number, such as 5
float: a decimal number, such as 3.14
bool: true or false
list: a list of values, such as [1, 2, 3]. list[str] is a list of texts.
dict: a set of keys and values, such as {"name": "Kitchen"}
datetime and timedelta: a date and time, and a duration. For details, refer to Dates and times.
None: no value
Any: any type of value

Some signatures use special forms:

*args means you can pass any number of values, separated by commas. For example, average(1, 2, 3).
value | name(...) means the function is a filter. The value before the | is passed to the filter as its first parameter. Some filter signatures, like the round example, show this value as the first parameter between the parentheses instead.

unique(
    value: list,
    case_sensitive: bool = False,
    attribute: str | None = None,
) -> list

Function parameters

The following parameters can be provided to this filter.

value list Required

The list to remove duplicates from.

case_sensitive boolean (Optional, default: false)

If true, “On” and “on” are treated as different values. Defaults to false.

attribute string (Optional)

Deduplicate based on this attribute of each item. Only the first item with each unique attribute value is kept.

Unique by attribute

Deduplicate a list of objects based on a specific attribute, keeping only the first object with each unique attribute value.

Template: One sensor per unique state value

{{
  expand("sensor.home_sensors")
  | unique(attribute="state")
  | map(attribute="entity_id")
  | list
}}

Result (list)

["sensor.kitchen_temp", "sensor.bedroom_temp"]

Good to know

Unlike Python’s standard behavior, this filter is case-insensitive by default. Pass case_sensitive=true if you want "On" and "on" treated as different values.
Returns a generator, so pipe the result through list if you need to loop over it more than once or display it directly.
The first occurrence of each value wins, preserving the original list order.

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.

Find distinct states across entities

Get the unique state values from a group of entities.

Template

{{
  expand("light.home_lights")
  | map(attribute="state")
  | unique
  | list
}}

Result (list)

["on", "off"]

Deduplicate a merged list

When combining entities from multiple sources, remove any that appear more than once.

Template

{% set list1 = ["light.kitchen", "light.bedroom", "light.hall"] %}
{% set list2 = ["light.bedroom", "light.porch", "light.kitchen"] %}
{{ (list1 + list2) | unique | list }}

Result (list)

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

Case-sensitive deduplication

By default, unique is case-insensitive. Use case_sensitive=true to treat different cases as distinct values.

Template

{{ ["On", "on", "OFF", "off"] | unique(case_sensitive=true) | list }}

Result (list)

["On", "on", "OFF", "off"]

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.

Tip

AI assistants like ChatGPT or Claude can also explain or fix templates when you describe what you want in plain language.

Related template functions

These functions work well alongside this one:

Convert to set: set - Converts an iterable to a set, removing duplicate values.
Sort a list: sort - Sorts the items in a list, with optional attribute-based and reverse sorting.
Filter items by test: select - Filters a list, keeping only items that pass a given test.
Group items by attribute: groupby - Groups a list of items by a common attribute, producing a list of (grouper, list) pairs.

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