# move(fromOffsets:toOffset:) Moves all the elements at the specified offsets to the specified destination offset, preserving ordering. ``` mutating func move(fromOffsets source: IndexSet, toOffset destination: Int) ``` ## Parameters `source` An index set representing the offsets of all elements that should be moved. `destination` The offset of the element before which to insert the moved elements. `destination` must be in the closed range `0...count`. ## Discussion Pass an offset as `destination` to indicate where in the collection the moved elements should be inserted. Of the elements that are not represented by the offsets in `source`, those before `destination` are moved toward the beginning of the collection to make room for the moved elements, while those at or after `destination` are moved toward the end. In this example, demonstrating moving several elements to different destination offsets, `lowercaseOffsets` represents the offsets of the lowercase elements in `letters`: ``` var letters = Array("ABcDefgHIJKlmNO") let lowercaseOffsets = IndexSet(...) letters.move(fromOffsets: lowercaseOffsets, toOffset: 2) // String(letters) == "ABcefglmDHIJKNO" // Reset the `letters` array. letters = Array("ABcDefgHIJKlmNO") letters.move(fromOffsets: lowercaseOffsets, toOffset: 15) // String(letters) == "ABDHIJKNOcefglm" ``` If `source` represents a single element, calling this method with its own offset, or the offset of the following element, as `destination` has no effect. ``` letters = Array("ABcDefgHIJKlmNO") letters.move(fromOffsets: IndexSet(integer: 2), toOffset: 2) // String(letters) == "ABcDefgHIJKlmNO" ``` > Complexity: O(*n* log *n*), where *n* is the length of the collection. --- 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)