计算列表中属性的总和 [英] Calculate SUM of a property in list

问题描述

我有以下课程:

public class Summary
{
        public string Name { get; set; }
        public string Marks { get; set; }
}

带有示例数据

SummaryList.Add(new ActivitySummary() { Name = "ATT",  Marks = "200"});
SummaryList.Add(new ActivitySummary() { Name =  "CHARTER",  Marks ="600"});

我想将另一个列表项添加到包含总计标记"属性的列表中.

I want to add another List item to the list that would contain Total of Marks property.

SummaryList.Add(new ActivitySummary() { Name =  "TOTAL",  Marks ="800"});

如何使用LINQ计算标记的总和?

How can I calculate the SUM of Marks property using LINQ?

推荐答案

要计算总和，请使用Sum:

SummaryList.Add(new ActivitySummary() {
    Name =  "TOTAL",
    Marks = SummaryList.Sum(item => Convert.ToInt32(item.Marks)).ToString()
});

如果您的Marks属性仅包含整数，则将其设置为string类型是没有意义的.如果查询的类型为int:

If your Marks property only contains integer numbers, making it of type string makes no sense. You can simplify the query if it is of type int:

public class Summary
{
    public string Name { get; set; }
    public int Marks { get; set; }
}

SummaryList.Add(new ActivitySummary() {
    Name =  "TOTAL",
    Marks = SummaryList.Sum(item => item.Marks)
});

如果您的Marks属性不是整数，请使用decimal，float或double代替int(分别是Convert.ToDecimal，Convert.ToSingle和Convert.ToDouble).

If your Marks property is not an integer number, use decimal, float or double instead of int (and Convert.ToDecimal, Convert.ToSingle and Convert.ToDouble respectively).

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