@r3dm4n的回答很棒。然而，我也需要一个小时。以防别人也需要，这里是:

func formatSecondsToString(_ seconds: TimeInterval) -> String {
    if seconds.isNaN {
        return "00:00:00"
    }
    let sec = Int(seconds.truncatingRemainder(dividingBy: 60))
    let min = Int(seconds.truncatingRemainder(dividingBy: 3600) / 60)
    let hour = Int(seconds / 3600)
    return String(format: "%02d:%02d:%02d", hour, min, sec)
}

Neek的答案不正确。

这是正确的版本

func seconds2Timestamp(intSeconds:Int)->String {
   let mins:Int = (intSeconds/60)%60
   let hours:Int = intSeconds/3600
   let secs:Int = intSeconds%60

   let strTimestamp:String = ((hours<10) ? "0" : "") + String(hours) + ":" + ((mins<10) ? "0" : "") + String(mins) + ":" + ((secs<10) ? "0" : "") + String(secs)
   return strTimestamp
}

根据GoZoner的答案，我写了一个扩展，以获得时间格式化根据小时，分钟和秒:

extension Double {

    func secondsToHoursMinutesSeconds () -> (Int?, Int?, Int?) {
        let hrs = self / 3600
        let mins = (self.truncatingRemainder(dividingBy: 3600)) / 60
        let seconds = (self.truncatingRemainder(dividingBy:3600)).truncatingRemainder(dividingBy:60)
        return (Int(hrs) > 0 ? Int(hrs) : nil , Int(mins) > 0 ? Int(mins) : nil, Int(seconds) > 0 ? Int(seconds) : nil)
    }

    func printSecondsToHoursMinutesSeconds () -> String {

        let time = self.secondsToHoursMinutesSeconds()

        switch time {
        case (nil, let x? , let y?):
            return "\(x) min \(y) sec"
        case (nil, let x?, nil):
            return "\(x) min"
        case (let x?, nil, nil):
            return "\(x) hr"
        case (nil, nil, let x?):
            return "\(x) sec"
        case (let x?, nil, let z?):
            return "\(x) hr \(z) sec"
        case (let x?, let y?, nil):
            return "\(x) hr \(y) min"
        case (let x?, let y?, let z?):
            return "\(x) hr \(y) min \(z) sec"
        default:
            return "n/a"
        }
    }
}

let tmp = 3213123.printSecondsToHoursMinutesSeconds() // "892 hr 32 min 3 sec"

最新代码:XCode 10.4 Swift 5

extension Int {
    func timeDisplay() -> String {
        return "\(self / 3600):\((self % 3600) / 60):\((self % 3600) % 60)"
    }
}

基于Vadian的回答，我写了一个扩展，它接受Double(其中TimeInterval是类型别名)，并输出一个格式化为时间的字符串。

extension Double {
  func asString(style: DateComponentsFormatter.UnitsStyle) -> String {
    let formatter = DateComponentsFormatter()
    formatter.allowedUnits = [.hour, .minute, .second, .nanosecond]
    formatter.unitsStyle = style
    return formatter.string(from: self) ?? ""
  }
}

这里是各种DateComponentsFormatter。UnitsStyle选项看起来像这样:

10000.asString(style: .positional)  // 2:46:40
10000.asString(style: .abbreviated) // 2h 46m 40s
10000.asString(style: .short)       // 2 hr, 46 min, 40 sec
10000.asString(style: .full)        // 2 hours, 46 minutes, 40 seconds
10000.asString(style: .spellOut)    // two hours, forty-six minutes, forty seconds
10000.asString(style: .brief)       // 2hr 46min 40sec

在Swift 5中:

    var i = 9897

    func timeString(time: TimeInterval) -> String {
        let hour = Int(time) / 3600
        let minute = Int(time) / 60 % 60
        let second = Int(time) % 60

        // return formated string
        return String(format: "%02i:%02i:%02i", hour, minute, second)
    }

调用函数

    timeString(time: TimeInterval(i))

会在02:44:57返回