Instance Method

update(with:)

Inserts the given element into the set unconditionally.

Declaration

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

Parameters

newMember: An element to insert into the set.

Return Value

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.

Discussion

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)"

Relationships

From Protocol

SetAlgebra