# init(_:) Creates a new set from a finite sequence of items. ``` init(_ sequence: Source) where Element == Source.Element, Source : Sequence ``` ## Parameters `sequence` The elements to use as members of the new set. ## Discussion Use this initializer to create a new set from an existing sequence, for example, an array or a range. ``` let validIndices = Set(0..<7).subtracting([2, 4, 5]) print(validIndices) // Prints "[6, 0, 1, 3]" ``` This initializer can also be used to restore set methods after performing sequence operations such as `filter(_:)` or `map(_:)` on a set. For example, after filtering a set of prime numbers to remove any below 10, you can create a new set by using this initializer. ``` let primes: Set = [2, 3, 5, 7, 11, 13, 17, 19, 23] let laterPrimes = Set(primes.lazy.filter { $0 > 10 }) print(laterPrimes) // Prints "[17, 19, 23, 11, 13]" ``` --- 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)