Find average of collection of TimeSpans

Question

I have collection of TimeSpans, they represent time spent doing a task. Now I would like to find the average time spent on that task. It should be easy but for some reason I'm not getting the correct average.

Here's my code:

private TimeSpan? GetTimeSpanAverage(List<TimeSpan> sourceList) {     TimeSpan total = default(TimeSpan);      var sortedDates = sourceList.OrderBy(x => x);      foreach (var dateTime in sortedDates)     {         total += dateTime;     }     return TimeSpan.FromMilliseconds(total.TotalMilliseconds/sortedDates.Count()); } 

Answer 1

You can use the Average overload that takes a collection of long in parameter:

double doubleAverageTicks = sourceList.Average(timeSpan => timeSpan.Ticks); long longAverageTicks = Convert.ToInt64(doubleAverageTicks);  return new TimeSpan(longAverageTicks); 

Answer 2

var average = new TimeSpan(sourceList.Select(ts => ts.Ticks).Average()); 

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Note, your method returns a Nullable, but doesn't need to, unless you want to return null if the source list is empty, in which case just do a separate check first.