# transformingAttributes(_:_:) Returns an attributed string by calling a closure that transforms one attribute of a source attributed string. ``` @preconcurrency func transformingAttributes(_ k: K.Type, _ c: (inout AttributedString.SingleAttributeTransformer) -> Void) -> AttributedString where K : AttributedStringKey, K.Value : Sendable ``` ## Parameters `k` The [`AttributedStringKey`](/documentation/Foundation/AttributedStringKey) that identifies the attribute to transform. `c` The closure that receives an [`AttributedString.SingleAttributeTransformer`](/documentation/Foundation/AttributedString/SingleAttributeTransformer) that you use to access and alter the attribute’s range and value. ## Return Value An attributed string with the applied transformation to the specified attribute. --- 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)