Performing operations on sets

Common values from both sets:

You can use the intersect(_:) method to create a new set containing all the values common to both sets.

let favoriteColors: Set = ["Red", "Blue", "Green"]
let newColors: Set = ["Purple", "Orange", "Green"]

let intersect = favoriteColors.intersect(newColors) // a AND b
// intersect = {"Green"}

All values from each set:

You can use the union(_:) method to create a new set containing all the unique values from each set.

let union = favoriteColors.union(newColors) // a OR b
// union = {"Red", "Purple", "Green", "Orange", "Blue"}

Notice how the value “Green” only appears once in the new set.

Values that don’t exist in both sets:

You can use the exclusiveOr(_:) method to create a new set containing the unique values from either but not both sets.

let exclusiveOr = favoriteColors.exclusiveOr(newColors) // a XOR b
// exclusiveOr = {"Red", "Purple", "Orange", "Blue"}

Notice how the value “Green” doesn’t appear in the new set, since it was in both sets.

Values that are not in a set:

You can use the subtract(_:) method to create a new set containing values that aren’t in a specific set.

let subtract = favoriteColors.subtract(newColors) // a - (a AND b)
// subtract = {"Blue", "Red"}

Notice how the value “Green” doesn’t appear in the new set, since it was also in the second set.