if num == .One || num == .Two || num == .Three || num == .Four {
    //code
}

switch num {
case .One, .Two. Three, .Four:
    //code
default:
    print("do nothing but I still need to put something here")
}

if case .One, .Two, .Three, .Four == num {
    //code
}

If [.One, .Two, .Three, .Four].contains(num) {

enum Number {
    case One, Two, Three, Four
}

switch num {
    case .One, .Two, Three, .Four:
        /* do something*/
        break
}