Replace occurrences in a string: replace

The replace filter replaces all occurrences of a substring within a string with a new value. You can optionally limit the number of replacements. This is useful when you need to clean up or transform text from sensorsSensors return information about a thing, for instance the level of water in a tank. [Learn more] and other sources. For example, you might want to remove units from a sensor value, replace underscores with spaces for a friendlier display name, or substitute specific words in a message before sending a notification.

Usage

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

{{ "Hello World" | replace("World", "Home Assistant") }}

Hello Home Assistant

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.

replace(
    value: str,
    old: str,
    new: str,
    count: int | None = None,
) -> str

Function parameters

The following parameters can be provided to this function.

Limiting the number of replacements

Pass a count to only replace the first N occurrences.

{{ "a-b-c-d" | replace("-", " ", 2) }}

a b c-d

Good to know

• Replaces every occurrence by default. Pass a count to limit the number of replacements.
• Only matches literal text. For patterns, use regex_replace.
• Case-sensitive. "ON" does not match "on".

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.

Make an entity ID more readable

Replace underscores with spaces to create a friendly name from an entity ID.

{{ "living_room_temperature" | replace("_", " ") | title }}

Living Room Temperature

Remove unwanted text from a sensor value

Strip a unit suffix from a sensor state so it can be processed as a number.

{{ "23.5 °C" | replace(" °C", "") | float }}

23.5

Clean up a notification message

Replace placeholder text in a message template.

{{ "Welcome home, {name}!" | replace("{name}", "Alice") }}

Welcome home, Alice!

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:

• Replace using a regex pattern: regex_replace - Replaces all occurrences of a regular expression pattern in a string.

• Strip whitespace: trim - Strips leading and trailing whitespace (or specified characters) from a string.

• Strip HTML tags: striptags - Removes all HTML/XML tags from a string, leaving only the text content.