在linq中使用group by

Question

我的列表包含factorId，amount，remain列。

我需要计算按amount

分别分组的总和remain和factorId列

Answer 1

var groupedList = myList.GroupBy(i => i.factorId);
var results = groupedList.Select(g => new { SumAmount = g.Sum(i => i.Amount), SumRemains = g.Sum(i => i.Remains) });

Answer 2

在一行中：

var groupedList = myList
    .GroupBy(i => i.factorId)
    .Select(g => new 
    { 
        FactorId = g.Key, 
        SumAmount = g.Sum(i => i.Amount), 
        SumRemains = g.Sum(i => i.Remains) 
    });