---
title: "formIndex(before:)"
framework: swift-package-manager
role: symbol
role_heading: Instance Method
path: "swift-package-manager/documentation/packageplugin/filelist/formindex(before:)"
---

# formIndex(before:)

Inherited from BidirectionalCollection.formIndex(before:).

## Declaration

```swift
func formIndex(before i: inout Self.Index)
```