LINQ - Count and sum duplicates in List<Tuple<int, double>>-CodePudding

Since I havent't used LINQ much, the following is a hard task for me: Having a list like List<Tuple<int, double>> I want to receive a List containing the amount (count) of duplicates of Item(1) and the corresponding sum of Item(2). The list should be orderd descending by the count of duplicates. How would a LINQ look like to get the result?

Thank you in advance. Rafael

CodePudding user response：

@JonasH explained the concept to achieve the result.

With these steps:

Group by Item1.
Perform count for grouped key and sum for total Item2.
Find duplicate Item1 with Count is greater than 1.
Order by Count descending.

var result = input.GroupBy(x => x.Item1)
            .Select(x => new
                    {
                        Item = x.Key,
                        Count = x.Count(),
                        Sum = x.Sum(y => y.Item2)
                    })
            .Where(x => x.Count > 1)
            .OrderBy(x => x.Count)
            .ToList();

Result