How to select values within a provided index range from a List using LINQ

c# linq list range
Punit Vora picture Punit Vora · Jun 25, 2009 · Viewed 63.7k times · Source

I am a LINQ newbie trying to use it to acheive the following:

I have a list of ints:-

List<int> intList = new List<int>(new int[]{1,2,3,3,2,1});

Now, I want to compare the sum of the first three elements [index range 0-2] with the last three [index range 3-5] using LINQ. I tried the LINQ Select and Take extension methods as well as the SelectMany method, but I cannot figure out how to say something like 

(from p in intList  
where p in  Take contiguous elements of intList from index x to x+n  
select p).sum()

I looked at the Contains extension method too, but that doesn't see to get me what I want. Any suggestions? Thanks.

Answer

Adam Sills picture Adam Sills · Jun 25, 2009

Use Skip then Take.

yourEnumerable.Skip(4).Take(3).Select( x=>x )

(from p in intList.Skip(x).Take(n) select p).sum()

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