c# – Linq Sum with group by

我有一个带有列的表结构

Feesnormal

FeesCustom

货币

现在我正在寻找按货币计算的SUM功能组.

例如20美元30欧元40 INR来自此表

如果FeesCustom>我还必须考虑这个场景. 0我必须忽略该行的Feesnormal

样本日期和预期结果是这样的

Feesnormal  FeesCustom  Currency
  10          0            USD   
  15          25           USD //in this case can ignore Feesnormal Since FeesCustom is more
  5           10           EUR //same for this row ignore Feesnormal
  10          0            EUR

Expected result  35 USD 20 EUR

我能够使用linq找到总和

int sum_custom=(int)fee_list.Where(p => p.FeesCustom > 0).Sum(p => p.FeesCustom);
 int sum_normal = (int)fee_list.Where(p => p.FeesCustom ==0).Sum(p => p.Feesnormal);

解决方法

在我看来,你只需要从“入门”到“有效费用”的预测,你可以总结 – 如：

var result = source
    .GroupBy(x => x.Currency)
    .Select(g => new {
        Currency = g.Key,Total = g.Sum(x => x.FeesCustom > 0 ? x.FeesCustom : x.Feesnormal)
    });

这相当于：

var result = source
    .GroupBy(x => x.Currency,(key,values) => new {
                Currency = key,Total = values.Sum(x => x.FeesCustom > 0 ? x.FeesCustom : x.Feesnormal)
             });

或者先进行转换：

var result = source
     .Select(x => new {
         x.Currency,x.Fee = x => x.FeesCustom > 0 ? x.FeesCustom : x.Feesnormal
     })
     .GroupBy(x => x.Currency,x => x.Fee,values) => new { Currency = key,Fee = values.Sum() });

原文地址：https://www.jb51.cc/csharp/97698.html