Swift – iOS – Dates and times in different format

func convertDateFormater(date: String) -> String {   
    let dateFormatter = NSDateFormatter()
    dateFormatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ss.SSSZ"
    dateFormatter.timeZone = NSTimeZone(name: "UTC")

    guard let date = dateFormatter.dateFromString(date) else {
        assert(false, "no date from string")
        return ""
    }

    dateFormatter.dateFormat = "yyyy MMM EEEE HH:mm"
    dateFormatter.timeZone = NSTimeZone(name: "UTC")
    let timeStamp = dateFormatter.stringFromDate(date)

    return timeStamp
}

Edit for Swift 4

func convertDateFormatter(date: String) -> String {
    let dateFormatter = DateFormatter()
    dateFormatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ss"//this your string date format
    dateFormatter.timeZone = NSTimeZone(name: "UTC") as TimeZone!
    dateFormatter.locale = Locale(identifier: "your_loc_id")
    let convertedDate = dateFormatter.date(from: date)

    guard dateFormatter.date(from: date) != nil else {
        assert(false, "no date from string")
        return ""
    } 

    dateFormatter.dateFormat = "yyyy MMM HH:mm EEEE"///this is what you want to convert format
    dateFormatter.timeZone = NSTimeZone(name: "UTC") as TimeZone!
    let timeStamp = dateFormatter.string(from: convertedDate!)

    return timeStamp
}