SWIFT中计算两个日期间隔多少小时

SWIFT中如何计算两个日期间隔多少个小时，其实几句代码就可以搞定了，Very Easy,在Playground内输入以下代码

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图片

如果要查看两个日期间隔多少天又该怎么做呢？

上面components的第一个参数为Hour那么应该也有Day吧，转到定义内看到如下的静态只读属性，改下这个参数后就可以获取间隔多少小时了。

    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 }