The flatten function provides an easy way to flatten a list of lists into a single list.
| Template function properties | |
|---|---|
| Function | Flatten a lists of lists |
| Function name | flatten |
| Returns | A flattened list |
| Return type | list of items |
| Can be used as a filter | Yes |
| Can be used as a test | No |
| Spook's influence | Newly added template function |
| Developer tools | Try this in the template developer tools |
| Signature |
|---|
|
| Function parameters | |||
|---|---|---|---|
| Attribute | Type | Required | Default / Example |
items | list of items | Yes | ["a", ["b", ["c"]]] |
levels | None, integer | No | None |
The levels parameter can be used to specify how many levels of lists should be
flattened. By default, all levels are flattened.
Examples¶
Using flatten as a function¶
1{{ flatten([1, [2, [3]], 4, [5 , 6]]) }}
Returns:
[1, 2, 3, 4, 5, 6]Using flatten as a filter¶
1{{ [1, [2, [3]], 4, [5 , 6]] | flatten }}
Returns:
[1, 2, 3, 4, 5, 6]Using a levels¶
You can define how many levels of lists should be flattened. By default, if no levels are specified, all levels are flattened.
Example:
1{{ flatten([1, [2, [3]]], levels=1) }}
Returns:
[1, 2, [3]]Features requests, ideas, and support¶
If you have an idea on how to further enhance the Home Assistant template engine, for example, by adding a new template function; feel free to let us know in our discussion forums.
Are you stuck using this new feature? Or maybe you’ve run into a bug? Please check the Support page on where to go for help.