---
title: "input(before:)"
framework: foundation
role: symbol
role_heading: Instance Method
path: "foundation/discreteformatstyle/input(before:)"
---

# input(before:)

The next input value before the given input.

## Declaration

```swift
func input(before input: Self.FormatInput) -> Self.FormatInput?
```

## Return Value

Return Value The next “smalller” input value that can be represented by FormatInput or an underlying representation the format style uses internally.

## Discussion

Discussion Use this function to determine if the return value provided by discreteInput(after:) is precise enough for your use case for any input y: guard let x = style.discreteInput(after: y) else {     return }

let z = style.input(before: x) ?? y If the distance between z and x is too large for the precision you require, you may want to manually probe format(_:) at a higher rate in that interval, as there is no guarantee for what the output will be in that interval.