# insert(_:within:) Inserts a range that contains only the specified index into the range set. ``` @discardableResult mutating func insert(_ index: Bound, within collection: C) -> Bool where Bound == C.Index, C : Collection ``` ## Parameters `index` The index to insert into the range set. `index` must be a valid index of `collection` that isn’t the collection’s `endIndex`. `collection` The collection that contains `index`. ## Return Value `true` if the range set was modified, or `false` if the given `index` was already in the range set. ## Discussion> Complexity: O(*n*), where *n* is the number of ranges in the range > set. --- 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)