# isSubset(of:) Returns a Boolean value that indicates whether the set is a subset of the given sequence. ``` func isSubset(of possibleSuperset: S) -> Bool where Element == S.Element, S : Sequence ``` ## Parameters `possibleSuperset` A sequence of elements. `possibleSuperset` must be finite. ## Return Value `true` if the set is a subset of `possibleSuperset`; otherwise, `false`. ## Discussion Set *A* is a subset of another set *B* if every member of *A* is also a member of *B*. ``` let employees = ["Alicia", "Bethany", "Chris", "Diana", "Eric"] let attendees: Set = ["Alicia", "Bethany", "Diana"] print(attendees.isSubset(of: employees)) // Prints "true" ``` --- 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)