Converting date and time to a string in Swift

let now = NSDate()

let shortStyle = NSDateFormatter.localizedStringFromDate(now,
    dateStyle: NSDateFormatterStyle.ShortStyle,
    timeStyle: NSDateFormatterStyle.ShortStyle)
//shortStyle is "6/22/15, 4:10 PM"

let dateFormatter = NSDateFormatter()
dateFormatter.dateFormat = "yyyy-MM-dd"
let customStyle = dateFormatter.stringFromDate(now)
//customStyle is "2015-06-22"