terraform/website/docs/language/functions/setsubtract.mdx

---
page_title: setsubtract - Functions - Configuration Language
description: |-
  The setsubtract function returns a new set containing the elements
  from the first set that are not present in the second set
---

⚠️⚠️⚠️⚠️⚠️⚠️⚠️⚠️⚠️⚠️⚠️⚠️
> [!IMPORTANT]  
> **Documentation Update:** Product documentation previously located in `/website` has moved to the [`hashicorp/web-unified-docs`](https://github.com/hashicorp/web-unified-docs) repository, where all product documentation is now centralized. Please make contributions directly to `web-unified-docs`, since changes to `/website` in this repository will not appear on developer.hashicorp.com.
⚠️⚠️⚠️⚠️⚠️⚠️⚠️⚠️⚠️⚠️⚠️⚠️


# `setsubtract` Function

The `setsubtract` function returns a new set containing the elements from the first set that are not present in the second set. In other words, it computes the
[relative complement](https://en.wikipedia.org/wiki/Complement_\(set_theory\)#Relative_complement) of the second set.

```hcl
setsubtract(a, b)
```

## Examples

```
> setsubtract(["a", "b", "c"], ["a", "c"])
toset([
  "b",
])
```

### Set Difference (Symmetric Difference)

```
> setunion(setsubtract(["a", "b", "c"], ["a", "c", "d"]), setsubtract(["a", "c", "d"], ["a", "b", "c"]))
toset([
  "b",
  "d",
])
```

## Related Functions

* [`setintersection`](/terraform/language/functions/setintersection) computes the _intersection_ of multiple sets
* [`setproduct`](/terraform/language/functions/setproduct) computes the _Cartesian product_ of multiple
  sets.
* [`setunion`](/terraform/language/functions/setunion) computes the _union_ of
  multiple sets.