有没有一种方法将C#泛型字典拆分成多个字典？

Question

我有一个C#字典Dictionary<MyKey, MyValue>，我想将其拆分为一组Dictionary<MyKey, MyValue>，基于MyKey.KeyType。 KeyType是一个枚举类型。

然后，我将得到一个包含键值对的字典，其中MyKey.KeyType = 1，另一个字典中MyKey.KeyType = 2，以此类推。

是否有一种不错的方法来做到这一点，例如使用Linq？

- Fiona - myaccessible.website

Answer 1

var dictionaryList = 
    myDic.GroupBy(pair => pair.Key.KeyType)
         .OrderBy(gr => gr.Key)  // sorts the resulting list by "KeyType"
         .Select(gr => gr.ToDictionary(item => item.Key, item => item.Value))
         .ToList(); // Get a list of dictionaries out of that

如果你想最终得到以"KeyType"为键的字典嵌套字典，方法类似：

var dictionaryOfDictionaries = 
    myDic.GroupBy(pair => pair.Key.KeyType)
         .ToDictionary(gr => gr.Key,         // key of the outer dictionary
             gr => gr.ToDictionary(item => item.Key,  // key of inner dictionary
                                   item => item.Value)); // value

- Mehrdad Afshari

Answer 2

我相信以下的代码会有效吗？

dictionary
    .GroupBy(pair => pair.Key.KeyType)
    .Select(group => group.ToDictionary(pair => pair.Key, pair => pair.Value);

- Sam Harwell

Answer 3

你可以使用GroupBy Linq函数：

            var dict = new Dictionary<Key, string>
                   {
                       { new Key { KeyType = KeyTypes.KeyTypeA }, "keytype A" },
                       { new Key { KeyType = KeyTypes.KeyTypeB }, "keytype B" },
                       { new Key { KeyType = KeyTypes.KeyTypeC }, "keytype C" }
                   };

        var groupedDict = dict.GroupBy(kvp => kvp.Key.KeyType);

        foreach(var item in groupedDict)
        {
            Console.WriteLine("Grouping for: {0}", item.Key);
            foreach(var d in item)
                Console.WriteLine(d.Value);
        }

- Venr

Answer 4

除非你只想要单独的集合：

Dictionary myKeyTypeColl<KeyType, Dictionary<MyKey, KeyVal>>

- IAbstract

Answer 5

所以你实际上想要一个类型为IDictionary<MyKey, IList<MyValue>>的变量吗？

- Unsliced

Answer 6

Dictionary <int,string> sports;
sports=new Dictionary<int,string>();
sports.add(0,"Cricket");
sports.add(1,"Hockey");
sports.add(2,"Badminton");
sports.add(3,"Tennis");
sports.add(4,"Chess");
sports.add(5,"Football");
foreach(var spr in sports)
console.WriteLine("Keu {0} and value {1}",spr.key,spr.value);

输出：

Key 0 and value Cricket
Key 1 and value Hockey
Key 2 and value Badminton
Key 3 and value Tennis
Key 4 and value Chess
Key 5 and value Football

- Mohammad Shahnawaz