# FormatInput The type this format style accepts as input. ``` associatedtype FormatInput ``` ## Discussion Swift type inference uses this value to determine which static accessors are available at a given call point. For example, when you format an , you can use the static [`number`](/documentation/Foundation/FormatStyle/number-4cj49) property that provies a `IntegerFormatStyle`, as seen in the following example. This works because the style’s input type `IntegerFormatStyle/FormatInput` is a generically constrained to the type. ```swift let perihelionDistanceToSunInKm: Int32 = 147098291 perihelionDistanceToSunInKm.formatted(.number .notation(.scientific)) // "1.470983E8" ``` --- 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)