init(_:)

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]"