Swift - Integer conversion to Hours/Minutes/Seconds

In macOS 10.10+ / iOS 8.0+ (NS)DateComponentsFormatter has been introduced to create a readable string.

It considers the user's locale und language.

let interval = 27005

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

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

The available unit styles are positional, abbreviated, short, full, spellOut and brief.

For more information please read the documenation.

Define

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)

The above function makes use of Swift tuples to return three values at once. You destructure the tuple using the let (var, ...) syntax or can access individual tuple members, if need be.

If you actually need to print it out with the words Hours etc then use something like this:

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

Note that the above implementation of secondsToHoursMinutesSeconds() works for Int arguments. If you want a Double version you'll need to decide what the return values are - could be (Int, Int, Double) or could be (Double, Double, Double). You could try something like:

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

Building upon Vadian's answer, I wrote an extension that takes a Double (of which TimeInterval is a type alias) and spits out a string formatted as time.

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) ?? ""
  }
}

Here are what the various DateComponentsFormatter.UnitsStyle options look like:

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