合并两个字典 Dictionary<string, Dictionary<string, Object>>

Question

这有点与这个问题有关，关于如何在 C# 中合并两个字典。提出了一个优雅的 Linq 解决方案，很酷。

然而，这个问题与Dictionary<Object1, Object2> 相关，而我有一本字典，其中的值为Dictionary<string, Object>。

我正在寻找合并两个Dictionary<string, Dictionary<string, Object>> 的解决方案，具有以下要求：

• 两个字典的字典结果中没有重复键，

• 对于每个字典，我认为按 KEY 分组可以成为解决方案的一部分，但在 ...

  internal static Dictionary<string, Dictionary<string, object>> OperationDic(Dictionary<string, Dictionary<string, object>> a, Dictionary<string, Dictionary<string, object>> b, string operation)`
      { 
          switch (operation) 
          {
              case "+":
                  var result =  a.Concat(b).GroupBy(d => d.Key).ToDictionary (d => d.Key, d => d.First().Value); 
                  return result;               
              default: 
  
                  throw new Exception("Fail ...");
          }             
      }
  

Answer 1

你应该问自己的第一个问题：合并两个字典的结果有什么类型？如果它们共享相同的键，如何将值合并在一起？

可能是这样的：

public static Dictionary<TKey, IEnumerable<TValue>> Merge<TKey, TValue>(this IDictionary<TKey, TValue> this_, IDictionary<TKey, TValue> other)
{
    return this_.Concat(other).     // IEnumerable<KeyValuePair<TKey, TValue>>
        GroupBy(kvp => kvp.Key).    // grouped by the keys
        ToDictionary(grp => grp.Key, grp => grp.Select(kvp => kvp.Value).Distinct());
}

所以Dictionary<string, Dictionary<string, object>> 类型的两个字典将转到Dictionary<string, IEnumerable<Dictionary<string, object>>>。

但是，您的值是字典，因此您可能需要合并它们：

public static Dictionary<TKey, IEnumerable<TValue>> Flatten<TKey, TValue>(IEnumerable<Dictionary<TKey, TValue>> dictionaries)
{
    return dictionaries.SelectMany(d => d.Keys).Distinct().         // IEnumerable<TKey> containing all the keys
        ToDictionary(key => key,
            key => dictionaries.Where(d => d.ContainsKey(key)).     // find Dictionaries that contain the key
                Select(d => d.First(kvp => kvp.Key.Equals(key))).   // select that key (KeyValuePair<TKey, TValue>)
                Select(kvp => kvp.Value));                          // and the value
}

这需要IEnumerable<Dictionary<string, object>> 并将其转换为Dictionary<string, IEnumerable<object>>。您现在可以为 Merge 生成的字典的每个值调用此方法。

电话是：

Dictionary<string, IEnumerable<Dictionary<string, object>>> result1 = dic1.Merge(dic2);
Dictionary<string, Dictionary<string, IEnumerable<object>>> result2 = dic1.Merge(dic2).ToDictionary(kvp => kvp.Key, kvp => Flatten(kvp.Value));

Answer 2

 internal static Dictionary<string, Dictionary<string, object>> OperationDic(Dictionary<string, Dictionary<string, object>> a, Dictionary<string, Dictionary<string, object>> b, string operation)
    {
        var result = new Dictionary<string, Dictionary<string, object>>(a);
        switch (operation)
        {
            case "+":                  
            // now check to see if we can add stuff from b
            foreach (var entryOuter in b)
            {
              Dictionary<string, object> existingValue;
              if (result.TryGetValue(entryOuter.Key, out existingValue))
              {
                  Dictionary<string, object> Value = entryOuter.Value;
                  result[entryOuter.Key] = existingValue.Concat(Value).GroupBy(d => d.Key).ToDictionary(d => d.Key, d => d.First().Value);
              }
              else
              {
                // new entry
                result.Add(entryOuter.Key, entryOuter.Value);
              }
            }
            return result;
            default:                    
                throw new Exception("FAIL ...");
        }
    }

Answer 3

我不太清楚你想要什么。这试图合并两个字典：

    // first copy everything from a
    var result = new Dictionary<string, Dictionary<string, object>>(a);

    // now check to see if we can add stuff from b
    foreach (var entryOuter in b)
    {
      Dictionary<string, object> existingValue;
      if (result.TryGetValue(entryOuter.Key, out existingValue))
      {
        // there's already an entry, see if we can add to it
        foreach (var entryInner in entryOuter.Value)
        {
          if (existingValue.ContainsKey(entryInner.Key))
            throw new Exception("How can I merge two objects? Giving up.");
          existingValue.Add(entryInner.Key, entryInner.Value);
        }
      }
      else
      {
        // new entry
        result.Add(entryOuter.Key, entryOuter.Value);
      }
    }

    return result;

您可能想要为null 添加检查。 a、b 和 existingValue（如果存在）可能是 null。

Answer 4

试试这个

var 结果 = a.Concat(b).GroupBy(c => c.Key).ToDictionary>(