Using a Swift String with NSData without NSString

Question

Is it possible to init a Swift string (not NSString) with the contents of an NSData object without creating an NSString first?

I know I can use this with NSString:

var datastring = NSString(data data: NSData!, encoding encoding: UInt) 

But how can I use a basic Swift String type? I thought Swift strings and NSStrings were interchangeable, do I really have to get the data out of NSData using NSString and then assign that value to a Swift string?

Answer 1

As of Swift 1.2 they aren't quite interchangeable, but they are convertible, so there's really no reason not to use NSString and its constructors when you need to. This will work fine:

var datastring = NSString(data:data, encoding:NSUTF8StringEncoding) as! String 

The as! is needed because NSString(...) can return nil for invalid input - if you aren't sure that the data represents a valid UTF8 string, you may wish to use the following instead to return a String? (aka Optional<String>).

var datastring = NSString(data:data, encoding:NSUTF8StringEncoding) as String? 

Once constructed, you can then use datastring just like any other Swift string, e.g.

var foo = datastring + "some other string"