# appendInterpolation(_:) Appends an attributed substring to a string interpolation. ``` @export(implementation) mutating func appendInterpolation(_ attributedSubstring: AttributedSubstring) ``` ## Parameters `attributedSubstring` The attributed substring to append. ## Discussion Don’t call this method directly; it’s used by the compiler when interpreting string interpolations. The following example shows how to use a string interpolation to format an and append it to static text. The resulting interpolation implicitly creates a [`LocalizedStringKey`](/documentation/SwiftUI/LocalizedStringKey), which a [`Text`](/documentation/SwiftUI/Text) view uses to provide its content. ``` struct ContentView: View { var identificationNumberSuffix: AttributedSubstring { // … } var body: some View { Text("Identification: •••• •••• \(identificationNumberSuffix)!") } } ``` For this example, assume that the app runs on a device set to a Russian locale, and has the following entry in a Russian-localized `Localizable.strings` file: ``` "Identification: •••• •••• %@" = "Идентификация: •••• •••• %@"; ``` The attributed string `identificationNumberSuffix` replaces the format specifier `%@`, maintaining its color attributes, when the [`Text`](/documentation/SwiftUI/Text) view renders its contents: --- 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)