---
title: "formUnion(with:)"
framework: foundation
role: symbol
role_heading: Instance Method
path: "foundation/nsmutablecharacterset/formunion(with:)"
---

# formUnion(with:)

Modifies the receiver so it contains all characters that exist in either the receiver or another set.

## Declaration

```swift
func formUnion(with otherSet: CharacterSet)
```

## See Also

### Combining Character Sets

- [formIntersection(with:)](foundation/nsmutablecharacterset/formintersection(with:).md)