Check out example codes for "c# groupby date". It will help you in understanding the concepts better.

Code Example 1

yourDateList.GroupBy(i => i.ToString("yyyyMMdd"))
             .Select(i => new
             {
                 Date = DateTime.ParseExact(i.Key, "yyyyMMdd", CultureInfo.InvariantCulture, DateTimeStyles.None),
                 Count = i.Count()
             });

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