Instance Method


Inserts the given element into the set unconditionally.

Required. Default implementation provided.


@discardableResult mutating func update(with newMember: Self.Element) -> Self.Element?



An element to insert into the set.

Return Value

For ordinary sets, an element equal to newMember if the set already contained such a member; otherwise, nil. In some cases, the returned element may be distinguishable from newMember by identity comparison or some other means.

For sets where the set type and element type are the same, like OptionSet types, this method returns any intersection between the set and [newMember], or nil if the intersection is empty.


If an element equal to newMember is already contained in the set, newMember replaces the existing element. In this example, an existing element is inserted into classDays, a set of days of the week.

enum DayOfTheWeek: Int {
    case sunday, monday, tuesday, wednesday, thursday,
        friday, saturday

var classDays: Set<DayOfTheWeek> = [.monday, .wednesday, .friday]
print(classDays.update(with: .monday))
// Prints "Optional(.monday)"

Default Implementations

OptionSet Implementations

func update(with: Self.Element) -> Self.Element?

Inserts the given element into the set.

See Also

Adding and Removing Elements

func insert(Self.Element) -> (inserted: Bool, memberAfterInsert: Self.Element)

Inserts the given element in the set if it is not already present.

Required. Default implementation provided.

func remove(Self.Element) -> Self.Element?

Removes the given element and any elements subsumed by the given element.

Required. Default implementation provided.