Linq和条件和 [英] Linq and conditional sum

问题描述

我有一个课程和一个清单，如下:

I have a class and a list as below:

class C1
{
    int RecType ...;
    decimal Income ...;
    decimal Outcome ...;
}

List<C1> myList ...;

该列表加载了多个记录，并且它们在RecType中具有各种值 我要计算的是收入"和结果"总计，但仅针对RecType的某个值

The list is loaded with several records, and they have various values in RecType What I want is to calculate total on Income and Outcome but only for a certain value of RecType

这是我需要获取的伪代码

Here's a pseudo code of what I need to get

totalIncome = myList.Sum(Income).Where(RecType==1);

如何使用linq完成此操作?

How can I accomplish this with linq?

谢谢

推荐答案

totalIncome = myList.Where(x => x.RecType == 1).Select(x => x.Income).Sum();

首先，您对记录类型(Where)进行过滤；然后通过Select转换每个对象的Income进行转换；最后，你Sum全部搞定了.

First you filter on the record type (Where); then you transform by Selecting the Income of each object; and finally you Sum it all up.

或更简洁的版本:

totalIncome = myList.Where(x => x.RecType == 1).Sum(x => x.Income);

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