Question

I have one composite dictionary and one list

Dictionary<Point, List<int>> GroupedIndex
List<double> TobeMatched

Now I want to create new dictionary with same key but with Values mapped by corresponding index from the GroupedIndex int values with TobeMatched index

Example:

GroupedIndex: [0] -> Key [X=1;Y=1]; Values [0] -> 5, [1] -> 10

TobeMatched: [0] 0.23 [5] 0.345 [10] 1.23

Result expected:
New dictionary: [0] -> Key[X=1;Y=1]; Values [0] -> 0.345, [1] -> 1.23

is it possible to linq to achieve the result efficiently. For loop is very inefficient.

Answer 1

GroupedIndex.ToDictionary(x => x.Key, 
                              x => x.Value.Select(y=>TobeMatched[y]).ToList());

That’s how you do this with LINQ. But I doubt it will be faster compared to regular loops.