使用LINQ反转和扁平化字典

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

class Program
{
    static void Main()
    {
        Dictionary<string, int> originalDict = new Dictionary<string, int>()
        {
            { "apple", 1 },
            { "banana", 2 },
            { "orange", 3 }
        };

        Dictionary<int, string> reversedDict = originalDict
            .ToDictionary(kvp => kvp.Value, kvp => kvp.Key);

        foreach (var kvp in reversedDict)
        {
            Console.WriteLine($"Key: {kvp.Key}, Value: {kvp.Value}");
        }
    }
}

Key: 1, Value: apple
Key: 2, Value: banana
Key: 3, Value: orange

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

class Program
{
    static void Main()
    {
        Dictionary<string, Dictionary<string, int>> nestedDict = new Dictionary<string, Dictionary<string, int>>()
        {
            {
                "fruit", new Dictionary<string, int>()
                {
                    { "apple", 1 },
                    { "banana", 2 }
                }
            },
            {
                "color", new Dictionary<string, int>()
                {
                    { "red", 3 },
                    { "blue", 4 }
                }
            }
        };

        var flattenedDict = nestedDict
            .SelectMany(outerKvp => outerKvp.Value.Select(innerKvp => new { outerKvp.Key, innerKvp.Key, innerKvp.Value }))
            .ToDictionary(kvp => $"{kvp.Key}_{kvp.Key}", kvp => kvp.Value);

        foreach (var kvp in flattenedDict)
        {
            Console.WriteLine($"Key: {kvp.Key}, Value: {kvp.Value}");
        }
    }
}

Key: fruit_apple, Value: 1
Key: fruit_banana, Value: 2
Key: color_red, Value: 3
Key: color_blue, Value: 4