---
title: "asciiOnlyCharacterClasses(_:)"
framework: swift
role: symbol
role_heading: Instance Method
path: "swift/regex/asciionlycharacterclasses(_:)"
---

# asciiOnlyCharacterClasses(_:)

Returns a regular expression that matches only ASCII characters when matching character classes.

## Declaration

```swift
func asciiOnlyCharacterClasses(_ useASCII: Bool = true) -> Regex<Regex<Output>.RegexOutput>
```

## Parameters

- `useASCII`: A Boolean value indicating whether to match only ASCII characters when matching character classes.

## Return Value

Return Value The modified regular expression.