How to calculate the sum of all values in a dictionary excluding the first item's value?

问题

I have a dictionary of (string, decimal) and need to calculate the sum of all the Values (decimal values) starting from the second item. Is it achievable using LINQ?

回答1:

Very achievable using LINQ:

myDict.Skip(1).Sum(x => x.Value);

However, the standard Dictionary class doesn't guarantee ordering of items, so the "first" item can be anything.

回答2:

Why not just sum them all up, then subtract the first item?

myList.Sum(x => x.Value) - myList.First().Value;

回答3:

Easy enough to do using LINQ:

var dict = new Dictionary<string, decimal>();

dict.Add("A", 1.5m); // This value will be skipped
dict.Add("B", 2.7m);
dict.Add("C", 1.3m);
dict.Add("D", 3.9m);

var total = dict.Skip(1).Sum(v => v.Value);

Console.WriteLine(total);

回答4:

Skip the first element thusly;

dict.Skip(1).Sum(ix => ix.Value);

来源：https://stackoverflow.com/questions/8128477/how-to-calculate-the-sum-of-all-values-in-a-dictionary-excluding-the-first-item