Test if mapping: mapping

The mapping test checks whether a value is a mapping type, such as a Python dictionary. It returns true if the value supports key-value access and false for lists, strings, numbers, and other types.

This is useful when working with entityAn 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] attributes or parsed JSON data that might be either a dictionary or a list. For example, some API responses return a dictionary for a single result and a list for multiple results. Testing with mapping lets you handle both cases correctly in your template.

Usage

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

{% if {"key": "value"} is mapping %}
  It is a mapping
{% endif %}

It is a mapping

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.

mapping(
    value: Any,
) -> bool

Function parameters

The following parameters can be provided to this test.

Good to know

• Only dictionary-like values pass. Lists, tuples, and strings do not, even though they may look similar.
• Use this to guard key access: dictionary access on a non-mapping raises an error.

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 various types

Dictionaries are mappings, but lists and strings are not.

{{ {"a": 1} is mapping }}
{{ [1, 2, 3] is mapping }}
{{ "hello" is mapping }}

true
false
false

Handle parsed JSON data

When parsing JSON that could be a dictionary or a list, check the type before accessing keys.

{% set data = '{"status": "ok"}' | from_json %}
{% if data is mapping %}
  Status: {{ data.status }}
{% else %}
  Unexpected format
{% endif %}

Status: ok

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:

• Test if iterable: iterable - Tests whether a value is iterable.

• Test if sequence: sequence - Tests whether a value is a sequence (list, tuple, or string).

• Parse JSON string: from_json - Parses a JSON string into a Python object.

• Get the type of a value: typeof - Returns the type name of a value as a string.