layout	page_title	sidebar_current	description
functions	flatten - Functions - Configuration Language	docs-funcs-collection-flatten	The flatten function eliminates nested lists from a list.

`flatten` Function

-> Note: This page is about Terraform 0.12 and later. For Terraform 0.11 and earlier, see 0.11 Configuration Language: Interpolation Syntax.

flatten takes a list and replaces any elements that are lists with a flattened sequence of the list contents.

Examples

> flatten([["a", "b"], [], ["c"]])
["a", "b", "c"]

If any of the nested lists also contain directly-nested lists, these too are flattened recursively:

> flatten([[["a", "b"], []], ["c"]])
["a", "b", "c"]

Indirectly-nested lists, such as those in maps, are not flattened.