Simple use of sets in Swift 5.

Sets.swift

//
// Simple use of sets
//

// basic set
var colors = Set(["yellow", "green", "green", "black", "purple"])
print(colors)     // ["purple", "yellow", "black", "green"]

colors.remove("green")
print(colors)     // ["black", "purple", "yellow"]

colors.insert("blue")
print(colors)     // ["blue", "black", "purple", "yellow"]


// empty set
var empty = Set<Int>()
empty.insert(1)
empty.insert(2)
empty.insert(3)
print(empty)     // [2, 3, 1]

empty.remove(3)
print(empty)     // [2, 1]