Log | Koffeinfrei

Nullable average in LINQ

Posted by myself on October 12, 2008

The following code is one possibility (there may be more elegant solutions to this) to handle a nullable average from a linq query. The problem arises when the linq query does not return a result, thus the average being null. If you don't use a nullable type, you'll get an exception. To get a nullable average from an integer value you'll need to provide a transform function to the Average funtion.


double? nullableAverage =
	(from m in dataContext.Moods
	 join g in dataContext.Groups on m.GroupGUID equals g.GUID
	 where g.GUID == groupGUID
	 select m.Level)
	.Average<int>(x => new double?(x));

int average = (int)Math.Round(nullableAverage.HasValue ? nullableAverage.Value : 0, 0);

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