# repetitionBehavior(_:) Returns a regular expression where quantifiers use the specified behavior by default. ``` func repetitionBehavior(_ behavior: RegexRepetitionBehavior) -> Regex.RegexOutput> ``` ## Parameters `behavior` The default behavior to use for quantifiers. ## Discussion This setting does not affect calls to quantifier methods, such as `OneOrMore`, that include an explicit `behavior` parameter. Passing `.eager` or `.reluctant` to this method corresponds to applying the `(?-U)` or `(?U)` option in regex syntax, respectively. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)