How do I get the App version and build number using Swift?

I have an IOS app with an Azure back-end, and would like to log certain events, like logins and which versions of the app users are running.

How can I return the version and build number using Swift?

EDIT

Updated for Swift 4.2

let appVersion = Bundle.main.infoDictionary?["CFBundleShortVersionString"] as? String

EDIT

As pointed out by @azdev on the new version of Xcode you will get a compile error for trying my previous solution, to solve this just edit it as suggested to unwrap the bundle dictionary using a !

let nsObject: AnyObject? = Bundle.main.infoDictionary!["CFBundleShortVersionString"]

End Edit

Just use the same logic than in Objective-C but with some small changes

//First get the nsObject by defining as an optional anyObject
let nsObject: AnyObject? = NSBundle.mainBundle().infoDictionary["CFBundleShortVersionString"]

//Then just cast the object as a String, but be careful, you may want to double check for nil
let version = nsObject as! String

I know this has already been answered but personally I think this is a little cleaner:

Swift 3.0:

 if let version = Bundle.main.infoDictionary?["CFBundleShortVersionString"] as? String {
    self.labelVersion.text = version
}

Swift <2.3

if let version = NSBundle.mainBundle().infoDictionary?["CFBundleShortVersionString"] as? String {
    self.labelVersion.text = version
}

This way, the if let version takes care of the conditional processing (setting the label text in my case) and if infoDictionary or CFBundleShortVersionString are nil the optional unwrapping will cause the code to be skipped.