# range(of:options:range:locale:) Finds and returns the range of the first occurrence of a given string within a given range of the `String`, subject to given options, using the specified locale, if any. ``` func range(of aString: T, options mask: String.CompareOptions = [], range searchRange: Range? = nil, locale: Locale? = nil) -> Range? where T : StringProtocol ``` --- 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)