Check if value contains another: contains

The contains template function checks whether one value is found inside another. It works with strings (substring search), lists (membership check), and dictionaries (key lookup). It uses Python’s in operator under the hood.

This is useful when you need to check if a sensorSensors return information about a thing, for instance the level of water in a tank. [Learn more] value includes a specific word, if a list of items includes a particular entry, or if a dictionary has a certain key. For example, you might want to check if a weather condition string contains “rain”, if a list of active devicesA device is a model representing a physical or logical unit that contains entities. includes a specific one, or filter 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] whose states contain a particular substring.

Usage

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

{{ "hello world" | contains("world") }}

true

{% if "hello world" is contains("world") %}
  Found it
{% endif %}

Found it

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 default are required.

contains(
    value: str | list | dict,
    item: Any,
) -> bool

Function parameters

The following parameters can be provided to this function.

Different container types

The contains function adapts to the type of value being searched.

String: {{ "automation running" | contains("running") }}
List: {{ [1, 2, 3] | contains(2) }}
Dict: {{ {"name": "test"} | contains("name") }}

String: true
List: true
Dict: true

Using as a test with select

Use contains as a test to filter lists of values.

{{
  ["sunny", "rainy day", "cloudy", "light rain"]
  | select("contains", "rain") | list
}}

['rainy day', 'light rain']

Good to know

• On dictionaries, this checks keys, not values. Use value in my_dict.values() when you need to match a value.
• String matching is case-sensitive. Pipe through | lower first to make it case-insensitive.
• Unlike in as a test, the argument order here is container first, item second.

Try it yourself

Ready to test this? Open Developer 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.

Check if a weather condition includes rain

Test the weather state to decide whether to send a reminder to bring an umbrella.

{% if states("weather.home") | contains("rain") %}
  Don't forget your umbrella!
{% else %}
  No rain expected
{% endif %}

Don't forget your umbrella!

Filter entities by state content

Find all sensors whose state contains a specific keyword.

{{
  ["online", "offline", "online - active", "standby"]
  | select("contains", "online") | list
}}

['online', 'online - active']

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:

• Check if entity has a value: has_value - Tests if an entity exists and has a valid state (not unavailable or unknown).

• Immediate if (ternary): iif - Shorthand for basic if/else logic in a single expression.