使用LINQ从列表中获取不同元素的计数

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

public class Program
{
    public static void Main()
    {
        List<int> numbers = new List<int> { 1, 2, 3, 2, 1, 3, 4, 5, 4, 5 };

        var counts = numbers
            .GroupBy(n => n)
            .Select(g => new { Number = g.Key, Count = g.Count() })
            .ToList();

        foreach (var count in counts)
        {
            Console.WriteLine($"Number: {count.Number}, Count: {count.Count}");
        }
    }
}

Number: 1, Count: 2
Number: 2, Count: 2
Number: 3, Count: 2
Number: 4, Count: 2
Number: 5, Count: 2