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

@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)
}

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

将数字转换为字符串形式的时间

func convertToHMS(number: Int) -> String {
  let hour    = number / 3600;
  let minute  = (number % 3600) / 60;
  let second = (number % 3600) % 60 ;
  
  var h = String(hour);
  var m = String(minute);
  var s = String(second);
  
  if h.count == 1{
      h = "0\(hour)";
  }
  if m.count == 1{
      m = "0\(minute)";
  }
  if s.count == 1{
      s = "0\(second)";
  }
  
  return "\(h):\(m):\(s)"
}
print(convertToHMS(number:3900))

来自@Gamec的答案

typealias CallDuration = Int

extension CallDuration {
    func formatedString() -> String? {
        let hours = self / 3600
        let minutes = (self / 60) % 60
        let seconds = self % 60
        if hours > 0 { return String(format: "%0.2d:%0.2d:%0.2d", hours, minutes, seconds) }
        return String(format: "%0.2d:%0.2d", minutes, seconds)
    }
}

用法:

let duration: CallDuration = 3000
duration.formatedString() // 50 minute

定义

func secondsToHoursMinutesSeconds(_ seconds: Int) -> (Int, Int, Int) {
    return (seconds / 3600, (seconds % 3600) / 60, (seconds % 3600) % 60)
}

Use

> secondsToHoursMinutesSeconds(27005)
(7,30,5)

or

let (h,m,s) = secondsToHoursMinutesSeconds(27005)

上面的函数使用Swift元组一次返回三个值。使用let (var，…)语法解构元组，如果需要，也可以访问单个元组成员。

如果你真的需要用Hours等文字打印出来，那么可以使用这样的东西:

func printSecondsToHoursMinutesSeconds(_ seconds: Int) {
  let (h, m, s) = secondsToHoursMinutesSeconds(seconds)
  print ("\(h) Hours, \(m) Minutes, \(s) Seconds")
}

注意，上面的secondstohoursminutessecseconds()实现适用于Int参数。如果你想要一个Double版本，你需要决定返回值是什么-可能是(Int, Int, Double)或可能是(Double, Double, Double)。你可以尝试这样做:

func secondsToHoursMinutesSeconds(seconds: Double) -> (Double, Double, Double) {
  let (hr,  minf) = modf(seconds / 3600)
  let (min, secf) = modf(60 * minf)
  return (hr, min, 60 * secf)
}