在一些简短的测试中，我发现两者的结合在我所谓的合理密集数学中会更好:

类型:<双[]>列表

时间:00:00:05.1861300

类型：列表<列表<double>>

时间:00:00:05.7941351

类型:double[行*列]

时间:00:00:06.0547118

运行代码:

int rows = 10000;
int columns = 10000;

IMatrix Matrix = new IMatrix(rows, columns);

Stopwatch stopwatch = new Stopwatch();
stopwatch.Start();


for (int r = 0; r < Matrix.Rows; r++)
    for (int c = 0; c < Matrix.Columns; c++)
        Matrix[r, c] = Math.E;

for (int r = 0; r < Matrix.Rows; r++)
    for (int c = 0; c < Matrix.Columns; c++)
        Matrix[r, c] *= -Math.Log(Math.E);


stopwatch.Stop();
TimeSpan ts = stopwatch.Elapsed;

Console.WriteLine(ts.ToString());

我真希望我们有一些顶尖的硬件加速矩阵类，就像。net团队用system . numbers . vectors类做的那样!

c#可能是最好的ML语言，只要在这方面多做一些工作!

对于@Marc Gravell的回答，我有两点需要澄清。

测试是在。net 6 x64版本中完成的。

测试代码结束。

数组和列表没有以相同的方式测试

为了在相同条件下测试array和List，还需要修改for。

for (int i = 0; i < arr.Length; i++)

新版本:

int len = arr.Length;
for (int i = 0; i < len; i++)

瓶颈列表/foreach:

List (List/foreach测试)的瓶颈是可以修复的。

改为:

list.ForEach(x => chk += x);

在Windows 10 pro 21H1 x64的笔记本电脑上测试运行，内核为i7-10510U

List/for Count out: 1495ms (589725196)
List/for Count in: 1706ms (589725196)
Array/for Count out: 945ms (589725196)
Array/for Count in: 1072ms (589725196)
List/foreach: 2114ms (589725196)
List/foreach fixed: 1210ms (589725196)
Array/foreach: 1179ms (589725196)

结果解释

数组/for比原始测试快。(减少12%)

List/foreach fixed比List/for快。

List/foreach fixed接近Array/foreach。

这个测试我已经运行了几次。结果改变了，但数量级保持不变。

这个测试的结果表明，您确实必须对性能有很大的需求才能强制使用Array。

根据用于操作List的方法，性能可以除以2。

这个测试是局部的。没有随机存取、直接存取、写存取测试等。

是我弄错了什么地方，还是你有其他提高性能的想法?

测试代码:

using System;
using System.Collections.Generic;
using System.Diagnostics;
static class Program
{
    static void Main()
    {        List<int> list = new List<int>(6000000);
        Random rand = new Random(12345);
        for (int i = 0; i < 6000000; i++)
        {
            list.Add(rand.Next(5000));
        }
        int[] arr = list.ToArray();

        int chk = 0;
        Stopwatch watch = Stopwatch.StartNew();
        for (int rpt = 0; rpt < 100; rpt++)
        {
            int len = list.Count;
            for (int i = 0; i < len; i++)
            {
                chk += list[i];
            }
        }
        watch.Stop();
        Console.WriteLine("List/for Count out: {0}ms ({1})", watch.ElapsedMilliseconds, chk);

        chk = 0;
        Stopwatch watch = Stopwatch.StartNew();
        for (int rpt = 0; rpt < 100; rpt++)
        {
            for (int i = 0; i < list.Count; i++)
            {
                chk += list[i];
            }
        }
        watch.Stop();
        Console.WriteLine("List/for Count in: {0}ms ({1})", watch.ElapsedMilliseconds, chk);

        chk = 0;
        watch = Stopwatch.StartNew();
        for (int rpt = 0; rpt < 100; rpt++)
        {
            int len = arr.Length;
            for (int i = 0; i < len; i++)
            {
                chk += arr[i];
            }
        }
        watch.Stop();
        Console.WriteLine("Array/for Count out: {0}ms ({1})", watch.ElapsedMilliseconds, chk);

        chk = 0;
        watch = Stopwatch.StartNew();
        for (int rpt = 0; rpt < 100; rpt++)
        {
            for (int i = 0; i < arr.Length; i++)
            {
                chk += arr[i];
            }
        }
        watch.Stop();
        Console.WriteLine("Array/for Count in: {0}ms ({1})", watch.ElapsedMilliseconds, chk);

        chk = 0;
        watch = Stopwatch.StartNew();
        for (int rpt = 0; rpt < 100; rpt++)
        {
            foreach (int i in list)
            {
                chk += i;
            }
        }
        watch.Stop();
        Console.WriteLine("List/foreach: {0}ms ({1})", watch.ElapsedMilliseconds, chk);

        chk = 0;
        watch = Stopwatch.StartNew();
        for (int rpt = 0; rpt < 100; rpt++)
        {
            list.ForEach(i => chk += i);
        }
        watch.Stop();
        Console.WriteLine("List/foreach fixed: {0}ms ({1})", watch.ElapsedMilliseconds, chk);

        chk = 0;
        watch = Stopwatch.StartNew();
        for (int rpt = 0; rpt < 100; rpt++)
        {
            foreach (int i in arr)
            {
                chk += i;
            }
        }
        watch.Stop();
        Console.WriteLine("Array/foreach: {0}ms ({1})", watch.ElapsedMilliseconds, chk);

        Console.ReadLine();
    }
}

如果你只是从其中一个中获得一个值(不是在循环中)，那么两者都进行边界检查(记住，你在托管代码中)，只是列表做了两次。 请参阅后面的注释，了解为什么这可能不是什么大问题。

如果你正在使用你自己的for(int int i = 0;i < x.[Length/Count];i++)则键差如下所示:

数组: 边界检查被移除 列表 执行边界检查

如果你使用foreach，关键区别如下:

数组: 没有分配对象来管理迭代 边界检查被移除 List通过一个已知为List的变量。 迭代管理变量是堆栈分配的 执行边界检查 列表通过一个已知为IList的变量。 迭代管理变量是堆分配的 执行边界检查 also Lists的值在foreach过程中不能改变，而数组的值可以改变。

边界检查通常不是什么大问题(特别是如果您在一个具有深层管道和分支预测的cpu上——这是目前大多数情况下的常态)，但只有您自己的分析才能告诉您这是否是一个问题。 如果你在代码中避免堆分配(很好的例子是库或hashcode实现)，那么确保变量类型为List而不是IList将避免这个陷阱。 和往常一样，如果重要的话。

static long[] longs = new long[500000];
static long[] longs2 = {};
static List<long> listLongs = new List<long> { };
static void Main(string[] args)
{
    Console.CursorVisible = false;
    Stopwatch time = new Stopwatch();

    time.Start();
    for (int f = 50000000; f < 50255000; f++)
    {
        listLongs.Add(f);
    }

    //List  Time: 1ms    Count : 255000
    Console.WriteLine("List Time: " + time.ElapsedMilliseconds + " | Count: " + listLongs.Count());

    time.Restart();
    time.Start();
    for (long i = 1; i < 500000; i++)
    {
        longs[i] = i * 200;
    }

    //Array Time: 2ms Length: 500000 (Unrealistic Data)
    Console.WriteLine("Array Time: " + time.ElapsedMilliseconds + " | Length: " + longs.Length);

    time.Restart();
    time.Start();
    for (int i = 50000000; i < 50055000; i++)
    {
        longs2 = longs2.Append(i).ToArray();
    }

    //Array Time: 17950ms Length: 55000
    Console.WriteLine("Array Append Time: " + time.ElapsedMilliseconds + " | Length: " + longs2.Length);

    Console.ReadLine();
}

如果您计划不断地向数组中添加少量数据，那么list更快

这实际上取决于你将如何使用数组。

实际上，如果在循环中执行一些复杂的计算，那么数组索引器与列表索引器的性能可能会非常小，最终，这无关紧要。

这是一个使用字典IEnumerable的例子:

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

static class Program
{
    static void Main()
    {
        List<int> list = new List<int>(6000000);

        for (int i = 0; i < 6000000; i++)
        {
                list.Add(i);
        }
        Console.WriteLine("Count: {0}", list.Count);

        int[] arr = list.ToArray();
        IEnumerable<int> Ienumerable = list.ToArray();
        Dictionary<int, bool> dict = list.ToDictionary(x => x, y => true);

        int chk = 0;
        Stopwatch watch = Stopwatch.StartNew();
        for (int rpt = 0; rpt < 100; rpt++)
        {
            int len = list.Count;
            for (int i = 0; i < len; i++)
            {
                chk += list[i];
            }
        }
        watch.Stop();
        Console.WriteLine("List/for: {0}ms ({1})", watch.ElapsedMilliseconds, chk);

        chk = 0;
        watch = Stopwatch.StartNew();
        for (int rpt = 0; rpt < 100; rpt++)
        {
            for (int i = 0; i < arr.Length; i++)
            {
                chk += arr[i];
            }
        }
        watch.Stop();
        Console.WriteLine("Array/for: {0}ms ({1})", watch.ElapsedMilliseconds, chk);

        chk = 0;
        watch = Stopwatch.StartNew();
        for (int rpt = 0; rpt < 100; rpt++)
        {
            foreach (int i in Ienumerable)
            {
                chk += i;
            }
        }

        Console.WriteLine("Ienumerable/for: {0}ms ({1})", watch.ElapsedMilliseconds, chk);

        chk = 0;
        watch = Stopwatch.StartNew();
        for (int rpt = 0; rpt < 100; rpt++)
        {
            foreach (int i in dict.Keys)
            {
                chk += i;
            }
        }

        Console.WriteLine("Dict/for: {0}ms ({1})", watch.ElapsedMilliseconds, chk);


        chk = 0;
        watch = Stopwatch.StartNew();
        for (int rpt = 0; rpt < 100; rpt++)
        {
            foreach (int i in list)
            {
                chk += i;
            }
        }

        watch.Stop();
        Console.WriteLine("List/foreach: {0}ms ({1})", watch.ElapsedMilliseconds, chk);

        chk = 0;
        watch = Stopwatch.StartNew();
        for (int rpt = 0; rpt < 100; rpt++)
        {
            foreach (int i in arr)
            {
                chk += i;
            }
        }
        watch.Stop();
        Console.WriteLine("Array/foreach: {0}ms ({1})", watch.ElapsedMilliseconds, chk);



        chk = 0;
        watch = Stopwatch.StartNew();
        for (int rpt = 0; rpt < 100; rpt++)
        {
            foreach (int i in Ienumerable)
            {
                chk += i;
            }
        }
        watch.Stop();
        Console.WriteLine("Ienumerable/foreach: {0}ms ({1})", watch.ElapsedMilliseconds, chk);

        chk = 0;
        watch = Stopwatch.StartNew();
        for (int rpt = 0; rpt < 100; rpt++)
        {
            foreach (int i in dict.Keys)
            {
                chk += i;
            }
        }
        watch.Stop();
        Console.WriteLine("Dict/foreach: {0}ms ({1})", watch.ElapsedMilliseconds, chk);

        Console.ReadLine();
    }
}