Averages/Mean time of day

Using the mean_angle() function from: "Averages/Mean angle"

func time2deg(t) {
  (var m = t.match(/^(\d\d):(\d\d):(\d\d)$/)) || die "invalid time"
  var (hh,mm,ss) = m.cap.map{.to_i}...
  ((hh ~~ 24.range) && (mm ~~ 60.range) && (ss ~~ 60.range)) || die "invalid time"
  (hh*3600 + mm*60 + ss) * 360 / 86400
}

func deg2time(d) {
  var sec = ((d % 360) * 86400 / 360)
  "%02d:%02d:%02d" % (sec/3600, (sec%3600)/60, sec%60)
}

func mean_time(times) {
  deg2time(mean_angle(times.map {|t| time2deg(t)}))
}

say mean_time(["23:00:17", "23:40:20", "00:12:45", "00:17:19"])

Output:

23:47:43