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

在macOS 10.10+ / iOS 8.0+ (NS)中，引入了DateComponentsFormatter来创建可读字符串。

它考虑用户的地区和语言。

let interval = 27005

let formatter = DateComponentsFormatter()
formatter.allowedUnits = [.hour, .minute, .second]
formatter.unitsStyle = .full

let formattedString = formatter.string(from: TimeInterval(interval))!
print(formattedString)

可用的单元样式有位置型、简写型、短型、全型、拼字型和简写型。

欲了解更多信息，请阅读文档。

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))

Xcode 12.1。Swift 5

DateComponentsFormatter:创建字符串表示的格式化程序， 通过使用unitsStyle，你可以得到一个你想要的字符串，并提到allowedUnits。 例如:output for unitsStyle:: for 10000秒

满=“2小时46分49秒” 位置= "2:46:40" 缩写为"2h 46m 40s" 拼写= " 2小时46分40秒" 短=“2小时46分40秒” 简短= "2小时46分40秒"

使用方便:

 let time = convertSecondsToHrMinuteSec(seconds: 10000)


func convertSecondsToHrMinuteSec(seconds:Int) -> String{
     let formatter = DateComponentsFormatter()
     formatter.allowedUnits = [.hour, .minute, .second]
     formatter.unitsStyle = .full
    
     let formattedString = formatter.string(from:TimeInterval(seconds))!
     print(formattedString)
     return formattedString
    }

恕我直言，最简单的方法是:

let hours = time / 3600
let minutes = (time / 60) % 60
let seconds = time % 60
return String(format: "%0.2d:%0.2d:%0.2d", hours, minutes, seconds)

斯威夫特5:

extension Int {

    func secondsToTime() -> String {

        let (h,m,s) = (self / 3600, (self % 3600) / 60, (self % 3600) % 60)

        let h_string = h < 10 ? "0\(h)" : "\(h)"
        let m_string =  m < 10 ? "0\(m)" : "\(m)"
        let s_string =  s < 10 ? "0\(s)" : "\(s)"

        return "\(h_string):\(m_string):\(s_string)"
    }
}

用法:

let seconds : Int = 119
print(seconds.secondsToTime()) // Result = "00:01:59"