如何找到从XML文档中抽取的一组5分的平均值？

Question

现在，它只是简单地显示每个分数的延迟。我想知道我如何才能准确地取得相同的成绩，并找到它们的平均值，并显示在页面底部。我不知道如何进一步阐明这个问题，但我肯定会回答与此有关的任何问题。

using System;
using System.Xml;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.IO;

namespace XML_Project1
{
    class Program
    {
        static void Main(string[] args)
        {
            int totalC = 0;
            XmlDocument xmlDoc = new XmlDocument();
            string XMLpath = Directory.GetCurrentDirectory() + @"\grades.xml";
            xmlDoc.Load(XMLpath);
            XmlNodeList Clist = xmlDoc.GetElementsByTagName("grade");
            totalC = Clist.Count;
            for (int i = 0; i < Clist.Count; i++)
            {
                Console.WriteLine(Clist[i].InnerText.ToString());
                System.Threading.Thread.Sleep(1000);
            }
            Console.WriteLine(Environment.NewLine);
            Console.WriteLine(totalC.ToString() + " people in XML file.");
            Console.ReadLine();
        }
    }
}

这是我正在绘制信息的XML文件。

<?xml version="1.0"?>
<class>
    <student>
        <name>Sam</name>
        <grade>76</grade>
    </student>
    <student>
        <name>Joe</name>
        <grade>80</grade>
    </student>
    <student>
        <name>Linda</name>
        <grade>82</grade>
    </student>
    <student>
        <name>Eugene</name>
        <grade>90</grade>
    </student>
    <student>
        <name>Tina</name>
        <grade>92</grade>
    </student>
</class>

Answer 1

试试看：

string XMLpath = Directory.GetCurrentDirectory() + @"\grades.xml";
XDocument xmlDoc = XDocument.Load(XMLpath);

IEnumerable<XElement> gradeElements = xmlDoc.Root.Descendants("grade");

int totalC = gradeElements.Count();
double averageGrade = gradeElements.Select(x => (double)x).Average();

Console.WriteLine(Environment.NewLine);
Console.WriteLine($"{totalC} people in XML file.");
Console.WriteLine($"{averageGrade} average grade.");
Console.ReadLine();

Answer 2

使用xml并将结果放入字典

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Xml;
using System.Xml.Linq;

namespace ConsoleApplication1
{
    class Program
    {
        const string FILENAME = @"c:\temp\test.xml";
        static void Main(string[] args)
        {
            XDocument doc = XDocument.Load(FILENAME);

            Dictionary<string, int> dict = doc.Descendants("student")
                .GroupBy(x => (string)x.Element("name"), y => (int)y.Element("grade"))
                .ToDictionary(x => x.Key, y => y.FirstOrDefault());

            decimal average = (decimal)dict.Average(x => x.Value);
        }
    }
}

Answer 3

您可以首先将每个元素转换为Int，而不是将其存储为XmlNode的集合。例如,

var Clist = xmlDoc.GetElementsByTagName("grade")
                  .Cast<XmlNode>()
                  .Select(x=> Convert.ToInt32(x.InnerText))
                  .ToList();

现在，您可以计算条目的数量(Peopl)和平均为

totalC = Clist.Count;
var average = Clist.Average();

完整代码

XmlDocument xmlDoc = new XmlDocument();
string XMLpath = @"e:\data.xml";
xmlDoc.Load(XMLpath);
var Clist = xmlDoc.GetElementsByTagName("grade")
                  .Cast<XmlNode>()
                  .Select(x=> Convert.ToInt32(x.InnerText))
                  .ToList();

var totalC = Clist.Count;
var average = Clist.Average();
for (int i = 0; i < Clist.Count; i++)
{
    Console.WriteLine(Clist[i]);
    System.Threading.Thread.Sleep(1000);

}
Console.WriteLine(Environment.NewLine);
Console.WriteLine($"{totalC} people in XML file.");
Console.WriteLine($"Average {average}");

请包括System.Linq命名空间