如何在C#中使用Linq从多个嵌套列中选择特定字符串？

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

public class Program
{
    public static void Main()
    {
        // 假设有一个包含多个嵌套列的数据结构
        List<List<string>> nestedList = new List<List<string>>
        {
            new List<string> { "apple", "banana", "cherry" },
            new List<string> { "orange", "grape", "kiwi" },
            new List<string> { "pear", "melon", "strawberry" }
        };

        // 使用Linq从多个嵌套列中选择特定字符串
        var selectedStrings = nestedList.SelectMany(x => x) // 展平嵌套列
                                       .Where(x => x.Contains("a")); // 筛选包含特定字符的字符串

        // 输出结果
        foreach (var str in selectedStrings)
        {
            Console.WriteLine(str);
        }
    }
}

apple
banana
grape
pear