---
page_title: concat - Functions - Configuration Language
description: The concat function combines two or more lists into a single list.
---

# `concat` Function

`concat` takes two or more lists and combines them into a single list.

## Examples

```
> concat(["a", ""], ["b", "c"])
[
  "a",
  "",
  "b",
  "c",
]

# Can do multiple lists of mixed types, arguments can also be empty lists
concat([], [1, "a"], [[3], "c"])
[
  1,
  "a",
  [
    3,
  ],
  "c",
]
```