将具有重复键的字典合并生成子字典

Question

我正在尝试合并两个包含 n 个嵌套字典的字典。合并的行为需要采用重复的键并创建一个字典作为它的值。例如，合并这两个字典：

Data_X: {
    Data_B: {
        Data_C: "C",
    }
}

Data_Z: {
    Data_B: {
        Data_F: "F",
    }
}

我希望这个合并结果：

Data_A: {
    Data_B: {
        Data_C: "C",
        Data_F: "F",
    }
}

似乎找不到任何解决方案，它不仅将“值”用于“F”或“C”，而是将下一个字典添加到“Data_B”的“值”属性中

到目前为止，这是我采用第一个“价值”而不是创建一个新价值的地方，但这并不完全正确：

Dictionary<string, object>[] dictionaries = new Dictionary<string, object>[]
{
    (Dictionary<string, object>)dictX, 
    (Dictionary<string, object>)dictZ
};

var result = dictionaries.SelectMany(dict => dict)
                         .ToLookup(pair => pair.Key, pair => pair.Value)
                         .ToDictionary(group => group.Key, group => group.First());

Answer 1

类似，并且作为一种扩展方法。

public static class DictionaryExtensions
{
    public static IDictionary<TKey, List<TValue>> Merge<TKey, TValue>(
        this IDictionary<TKey, TValue> me,
        IDictionary<TKey, TValue> other
    )
    {
        var keys = me.Concat(other)
            .GroupBy(x => x.Key)
            .ToDictionary(
                x => x.Key,
                x => x.Select(z => z.Value).ToList()
            );
        return keys;
    }
}

用法：

var dic1 = new Dictionary<string, string> { { "B", "C" }, { "A", "X" } };
var dic2 = new Dictionary<string, string> { { "B", "F" }, { "D", "D" } };
var dicm = dic1.Merge(dic2);

更新：

使用这些扩展方法，您可以继续合并。

public static IDictionary<TKey, List<TValue>> Merge<TKey, TValue>(this IDictionary<TKey, List<TValue>> me, IDictionary<TKey, List<TValue>> other)
{
    var keys = me.Concat(other)
        .GroupBy(x => x.Key)
        .ToDictionary(
            x => x.Key,
            x => x.SelectMany(z => z.Value).ToList()
        );
    return keys;
}

public static IDictionary<TKey, List<TValue>> Merge<TKey, TValue>(this IDictionary<TKey, List<TValue>> me, IDictionary<TKey, TValue> other)
{
    return me
        .Merge(
            other
                .ToDictionary(
                    x => x.Key,
                    x => new List<TValue> { x.Value }
                )
        );
}

用法：

var dic1 = new Dictionary<string, string> { { "B", "C" }, { "A", "X" } };
var dic2 = new Dictionary<string, string> { { "B", "F" }, { "D", "D" } };
var dic3 = new Dictionary<string, string> { { "B", "F" }, { "E", "D" } };
var dic4 = new Dictionary<string, string> { { "X", "F" }, { "E", "D" } };
var dicm = dic1.Merge(dic2).Merge(dic3).Merge(dic4);

Answer 2

你只需要一点老式的递归。这假设字典的结构是兼容的，并且不对尝试合并字典和字符串值进行错误检查。

    Dictionary<string, object> MergeDictionary(IEnumerable<Dictionary<string, object>> dicts)
    {
        var l = dicts.SelectMany(d => d).ToLookup(kv => kv.Key, kv => kv.Value);
        return l.ToDictionary(
            g => g.Key,
            g => g.Count() == 1
                ? g.First()
                : MergeDictionary(g.Cast<Dictionary<string, object>>()));
    }

要对其进行测试，您可以运行它，它会返回您想要的结果。

    static void TestMergeDictionary()
    {
        var dbx = new Dictionary<string, object> { { "Data_C", "C" } };
        var dx = new Dictionary<string, object> { { "Data_B", dbx } };

        var dbz = new Dictionary<string, object> { { "Data_F", "F" } };
        var dz = new Dictionary<string, object> { { "Data_B", dbz } };

        var da = MergeDictionary(new[] { dx, dz });
    }

Answer 3

与其获取.First()，不如直接返回.ToList()？这将为您提供所有字典中的键及其所有关联值。

var x = new Dictionary<string, object>();
x.Add("B", "F");
x.Add("A", "D");
var y = new Dictionary<string, object>();
y.Add("B", "G");
Dictionary<string, object>[] dictionaries = new Dictionary<string, object>[]
{
        x,
        y
};

var result = dictionaries.SelectMany(dict => dict)
                     .ToLookup(pair => pair.Key, pair => pair.Value)
                     .ToDictionary(group => group.Key, group => group.ToList()); /* here */

返回（来自 C# 交互式 shell，所以格式化有点奇怪）：

 Dictionary<string, List<object>>(2) { 
        { "B", List<object>(2) { "F", "G" } }, 
        { "A", List<object>(1) { "D" } } 
    }