# init(set:copyItems:) Initializes a newly allocated set and adds to it members of another given set. ``` convenience init(set: Set, copyItems flag: Bool) ``` ## Parameters `set` A set containing objects to add to the new set. `flag` If , each object in `set` receives a message to create a copy of the object—objects must conform to the `NSCopying` protocol. In a managed memory environment, this is instead of the `retain` message the object would otherwise receive. The object copy is then added to the returned set. If , then in a managed memory environment each object in `set` simply receives a `retain` message when it is added to the returned set. ## Return Value An initialized set that contains the members of `set`. The returned set might be different than the original receiver. ## Discussion After an immutable s has been initialized in this way, it cannot be modified. The [`copy(with:)`](/documentation/Foundation/NSCopying/copy(with:)) method performs a shallow copy. If you have a collection of arbitrary depth, passing for the `flag` parameter will perform an immutable copy of the first level below the surface. If you pass the mutability of the first level is unaffected. In either case, the mutability of all deeper levels is unaffected. ## See Also [`initWithObjects:`](/documentation/Foundation/NSSet/initWithObjects:) Initializes a newly allocated set with members taken from the specified list of objects. [`setWithSet:`](/documentation/Foundation/NSSet/setWithSet:) Creates and returns a set containing the objects from another 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)