//获取当前距1970时间戳    func getNowTimestamp() -> Int{                let date = NSDate.init()        return Int(date.timeIntervalSince1970)            }     /*     *获取指定距1970时间戳      格式: "yyyy-MM-dd HH:mm:ss"    */    func getOtherTimestamp(timesDateString:String) ->Int{        let df = DateFormatter.init()        df.dateFormat = "yyyy-MM-dd HH:mm:ss"        let ds = df.date(from: timesDateString)                return Int((ds?.timeIntervalSince1970)!)    }        func test(){        //两个时间对比        print(getNowTimestamp() - getOtherTimestamp(timesDateString: "2017-07-29 14:20:01"))    }