I have array

 int[] arr = { -2, 0, 1, 2, 3, 4, 5, 8, 9, 11, 13, 15, 18, 22, 25, 28, 29, 30 }; 

I need to write function that shows it as string and if numbers are near, like 1,2,3,4,5 – I need to show them 1-5.

I wrote this function in repository

  public string[] GetArray()     {         int[] arr = { -2, 0, 1, 2, 3, 4, 5, 8, 9, 11, 13, 15, 18, 22, 25, 28, 29, 30 };          int? lastValue = arr.FirstOrDefault();          var groupDataIntoAdjacentBlocks = arr.Segment(i =>         {             var result = lastValue != null && (lastValue != (i - 1));             lastValue = i;             return result;         }         );          var convertSetsIntoRanges = groupDataIntoAdjacentBlocks.Select(z =>         {             var data = z.ToList();             if (data.Count() == 1)                 return data.First().ToString();              return data.First().ToString() + "-" + data.Last().ToString();         });          var finalresult = (string.Join(",", convertSetsIntoRanges));         return new[] { finalresult };      } 

And call it like this in controller

 public JsonResult GetArray()     {         var arrayresult = _arrayrepo.GetArray();         return Json(arrayresult, JsonRequestBehavior.AllowGet);     } 

Any suggestions how I can improve my code?