---
title: "init(_:)"
framework: swift
role: symbol
role_heading: Initializer
path: "swift/reversedcollection/index/init(_:)"
---

# init(_:)

Creates a new index into a reversed collection for the position before the specified index.

## Declaration

```swift
init(_ base: Base.Index)
```

## Parameters

- `base`: The position after the element to create an index for.

## Discussion

Discussion When you create an index into a reversed collection using base, an index from the underlying collection, the resulting index is the position of the element before the element referenced by base. The following example creates a new ReversedIndex from the index of the "a" character in a string’s character view. let name = "Horatio" let aIndex = name.firstIndex(of: "a")! // name[aIndex] == "a"

let reversedName = name.reversed() let i = ReversedCollection<String>.Index(aIndex) // reversedName[i] == "r" The element at the position created using ReversedIndex<...>(aIndex) is "r", the character before "a" in the name string.