SWIFT中計算兩個日期間隔多少小時

SWIFT中如何計算兩個日期間隔多少個小時，其實幾句代碼就可以搞定了，Very Easy,在Playground內輸入以下代碼

var date1 = "2015-06-26 8:15:10"
var dateformatter = NSDateFormatter()
dateformatter.dateFormat = "yyyy-MM-dd hh:mm:ss"
var dateresult = dateformatter.dateFromString(date1)

NSDate()

var gregorian = NSCalendar(calendarIdentifier: NSCalendarIdentifierGregorian)
var result = gregorian!.components(NSCalendarUnit.CalendarUnitHour, fromDate: dateresult!, toDate: NSDate(), options: NSCalendarOptions(0))

result.hour

 附上Playgroud圖片

如果要查看兩個日期間隔多少天又該怎么做呢？

上面components的第一個參數為Hour那么應該也有Day吧，轉到定義內看到如下的靜態只讀屬性，改下這個參數后就可以獲取間隔多少小時了。

    static var CalendarUnitEra: NSCalendarUnit { get }
    static var CalendarUnitYear: NSCalendarUnit { get }
    static var CalendarUnitMonth: NSCalendarUnit { get }
    static var CalendarUnitDay: NSCalendarUnit { get }
    static var CalendarUnitHour: NSCalendarUnit { get }
    static var CalendarUnitMinute: NSCalendarUnit { get }
    static var CalendarUnitSecond: NSCalendarUnit { get }
    static var CalendarUnitWeekday: NSCalendarUnit { get }
    static var CalendarUnitWeekdayOrdinal: NSCalendarUnit { get }