# insert(contentsOf:at:) Inserts a collection of characters at the specified position. ``` mutating func insert(contentsOf newElements: S, at i: String.Index) where S : Collection, S.Element == Character ``` ## Parameters `newElements` A collection of `Character` elements to insert into the string. `i` A valid index of the string. If `i` is equal to the string’s end index, this methods appends the contents of `newElements` to the string. ## Discussion Calling this method invalidates any existing indices for use with this string. > Complexity: O(*n*), where *n* is the combined length of the string and > `newElements`. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)