---
title: "index(_:offsetBy:)"
framework: swift
role: symbol
role_heading: Instance Method
path: "swift/string/utf16view/index(_:offsetby:)"
---

# index(_:offsetBy:)

Returns an index that is the specified distance from the given index.

## Declaration

```swift
func index(_ i: String.UTF16View.Index, offsetBy n: Int) -> String.UTF16View.Index
```

## Parameters

- `i`: A valid index of the collection.

## Return Value

Return Value An index offset by distance from the index i. If distance is positive, this is the same value as the result of distance calls to index(after:). If distance is negative, this is the same value as the result of abs(distance) calls to index(before:).

## Discussion

Discussion The following example obtains an index advanced four positions from a string’s starting index and then prints the character at that position. let s = "Swift" let i = s.index(s.startIndex, offsetBy: 4) print(s[i]) // Prints "t" The value passed as distance must not offset i beyond the bounds of the collection. note: O(1) if the collection conforms to RandomAccessCollection; otherwise, O(k), where k is the absolute value of distance.