---
title: "formIndex(before:)"
framework: foundation
role: symbol
role_heading: Instance Method
path: "foundation/indexset/formindex(before:)"
---

# formIndex(before:)

Modifies the given index to refer to the item before the one it currently refers to.

## Declaration

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

## See Also

### Manipulating Indexes

- [startIndex](foundation/indexset/startindex.md)
- [endIndex](foundation/indexset/endindex.md)
- [index(after:)](foundation/indexset/index(after:).md)
- [index(before:)](foundation/indexset/index(before:).md)
- [formIndex(after:)](foundation/indexset/formindex(after:).md)
- [indexRange(in:)](foundation/indexset/indexrange(in:)-539lz.md)