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iOS Swift Enums and Structs Enums What is an Enum?

Posted by Ryan Lail
Ryan Lail
4,386 Points

Can you use string interpolation with enum?

In the results pane doesn't show the day when i've used string interpolation (not sure if i've got that spelling right) - but rather it shows '(Enum Value)'

http://www.mediafire.com/view/e1171cyd0et6cio/Screen_Shot_2015-08-13_at_21.54.17.png

2 Answers

Andrew Rodko
Andrew Rodko
27,881 Points
Andrew Rodko
Andrew Rodko
27,881 Points

Yeah, to convert an enum to a string you'd need to specify the string value for each enum. One way to do this is with raw values. So your enum would become:

enum Day: String { case Monday = "Monday" case Tuesday = "Tuesday" etc.... }

Your string interpolations would then become (dayOfWeek.rawValue) instead of (dayOfWeek)

You could also clean it up a bit by moving your function inside your enum. If you do that, the function would become:

func weekdayOrWeekend() -> String { switch self { case .Monday, etc...: return "(self.rawValue) is a weekday!" and so on... } }

Ryan Lail
Ryan Lail
4,386 Points

Thanks for the help! Do you think you could explain the moving my function inside my enum part a bit more. It looks very interesting but I'm a bit confused about how to do it? Thank you once again!

Andrew Rodko
Andrew Rodko
27,881 Points
Andrew Rodko
Andrew Rodko
27,881 Points

Sure, here's what your entire enum would like like. After moving the function inside the enum, you just need to remove the dayOfWeek input parameter from the function, and replace any reference to this parameter inside the function with "self." Calling the function would then be done like this:

var today = Day.Monday today.weekdayOrWeekend()

or

Day.Monday.weekdayOrWeekend()

enum Day: String { case Monday = "Monday" case Tuesday = "Tuesday" case Wednesday = "Wednesday" case Thursday = "Thursday" case Friday = "Friday" case Saturday = "Saturday" case Sunday = "Sunday"

func weekdayOrWeekend() -> String {
    switch self {
    case .Monday, .Tuesday, .Wednesday, .Thursday, .Friday:
        return "\(self.rawValue) is a weekday!"
    case .Saturday, .Sunday:
        return "YAAAAHHHH! It's \(self.rawValue)! Time to put the fun in party.  Wait... fun isn't in party. Well- this is awkward :o"
    default:
        return "Buddy, that's not even a day.  Are you drunk?"
    }
}

}

Jhoan Arango
Jhoan Arango
14,575 Points
Jhoan Arango
Jhoan Arango
14,575 Points

Hey Ryan : I’m using the latest version of swift, and Xcode and can’t post any screenshots until is out of beta. But I am not 100% sure, but I think what you are trying to do is possible in swift 2.0 and the latest Xcode releases. This is my code 

enum Day {
    case Monday, Tuesday
}


func whatday(enumDay: Day) {

    switch enumDay {
    case .Monday, .Tuesday :
        print("The day is \(enumDay)")
    }

}
whatday(Day.Monday)


// on the results pain shows me “The day is Monday"

So perhaps its an upgrade coming up with the latest versions of Swift and Xcode. I think I did see on the apple’s Swifts 2.0 new features keynote video something about swift not showing “Enum Value” anymore.

Hope this information helps

Ryan Lail
Ryan Lail
4,386 Points

Thanks, looking forward for Swift 2.0's release!!!