按平均考试成绩降序分组？答案

【问题标题】：Group by descending average test score?按平均考试成绩降序分组？
【发布时间】：2021-05-03 22:26:27
【问题描述】：

我需要 LINQ 方面的帮助，我需要根据计算出的平均水平对学生列表进行分组有一个学生班：

public class Student
{
    public string Name { get; set; }  // student name
    public int[] Scores { get; set; } // test scores
}

我有一份包含数据的学生列表

List<Student> students = new List<Student>
{
    new Student { Name = "Michael", Scores = new int[] { 94, 92, 91, 91 } },
    new Student { Name = "Isabelle", Scores = new int[] { 66, 87, 65, 93, 86} },
    new Student { Name = "Chastity", Scores = new int[] { 76, 61, 73, 66, 54} },
    new Student { Name = "Chaim", Scores = new int[] { 94, 55, 82, 62, 52} },
    new Student { Name = "Patience", Scores = new int[] { 91, 79, 58, 63, 55} },
    new Student { Name = "Echo", Scores = new int[] { 74, 85, 73, 75, 86} },
    new Student { Name = "Pamela", Scores = new int[] { 73, 64, 53, 72, 68} },
    new Student { Name = "Anne", Scores = new int[] { 78, 96, 52, 79, 60} },
    new Student { Name = "Fuller", Scores = new int[] { 59, 68, 88, 85, 76} },
    new Student { Name = "Cameron", Scores = new int[] { 70, 73, 75, 51, 98} },
    new Student { Name = "Aurora", Scores = new int[] { 65, 70, 53, 80, 52} },
    new Student { Name = "Anthony", Scores = new int[] { 68, 69, 94, 88, 98} },
}

我需要范围的括号在测试分数括号中是 10 的倍数 • 50、60、70、80、90、100

输出应如下所示：

【问题讨论】：

Tobit Sabu 你能澄清一下你的问题吗？
你是如何对数据进行排序的？
我刚刚添加了输出。
@TobitSabu 看看我的回答

标签： c# linq c#-2.0

【解决方案1】：

我想是这样的吗？

结果：

--------------------------
90
Name: Michael
--------------------------

--------------------------
80
Name: Isabelle
Name: Echo
Name: Fuller
Name: Anthony
--------------------------

--------------------------
70
Name: Chastity
Name: Chaim
Name: Patience
Name: Pamela
Name: Anne
Name: Cameron
--------------------------

--------------------------
60
Name: Aurora
--------------------------

代码：

using System;
using System.Collections.Generic;
using System.Linq;

namespace ConsoleApp1
{
    internal static class Program
    {
        private static void Main()
        {
            var students = new List<Student>
            {
                new() {Name = "Michael", Scores = new[] {94, 92, 91, 91}},
                new() {Name = "Isabelle", Scores = new[] {66, 87, 65, 93, 86}},
                new() {Name = "Chastity", Scores = new[] {76, 61, 73, 66, 54}},
                new() {Name = "Chaim", Scores = new[] {94, 55, 82, 62, 52}},
                new() {Name = "Patience", Scores = new[] {91, 79, 58, 63, 55}},
                new() {Name = "Echo", Scores = new[] {74, 85, 73, 75, 86}},
                new() {Name = "Pamela", Scores = new[] {73, 64, 53, 72, 68}},
                new() {Name = "Anne", Scores = new[] {78, 96, 52, 79, 60}},
                new() {Name = "Fuller", Scores = new[] {59, 68, 88, 85, 76}},
                new() {Name = "Cameron", Scores = new[] {70, 73, 75, 51, 98}},
                new() {Name = "Aurora", Scores = new[] {65, 70, 53, 80, 52}},
                new() {Name = "Anthony", Scores = new[] {68, 69, 94, 88, 98}}
            };

            var groups = students.GroupBy(s => Math.Round(s.Scores.Average() / 10) * 10).OrderByDescending(s => s.Key);

            foreach (var grouping in groups)
            {
                Console.WriteLine("--------------------------");

                Console.WriteLine(grouping.Key);

                foreach (var student in grouping)
                {
                    Console.WriteLine(student);
                }

                Console.WriteLine("--------------------------");
                Console.WriteLine();
            }
        }
    }

    public class Student
    {
        public string Name { get; set; }

        public int[] Scores { get; set; }

        public override string ToString()
        {
            return $"{nameof(Name)}: {Name}";
        }
    }
}

【讨论】：