Performance of a get unique elements/group by operation on an IEnumerable<T>.
- by tolism7
I was wondering how could I improve the performance of the following code:
public class MyObject
{
public int Year { get; set; }
}
//In my case I have 30000
IEnumerable<MyObject> data = MethodThatReturnsManyMyObjects();
var groupedByYear = data.GroupBy(x => x.Year);
//Here is the where it takes around 5 seconds
foreach (var group in groupedByYear)
//do something here.
The idea is to get a set of objects with unique year values. In my scenario there are only 6 years included in the 30000 items in the list so the foreach loop will be executed 6 times only. So we have many items needing to be grouped in a few groups.
Using the .Distinct() with an explicit IEqualityComparer would be an alternative but somehow I feel that it wont make any difference.
I can understand if 30000 items is too much and that i should be happy with the 5 seconds I get, but I was wondering if the above can be imporved performance wise.
Thanks.
