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c#.netdictionary
AksharRoop
AksharRoop

Reputation: 2293

How to convert ValueCollection to Dictionary?

I've a dictionary member of type Dictionary<string, Dictionary<string, List<SomeType>>>. What I want is to get nested dictionary from this i.e. Dictionary<string, List<SomeType>>. I thought I'd get this using myDict.Values, but that's actually returning ValueCollection and not the nested-dictionary itself.

Now I'm trying to get this done using ValueCollection.ToDictionary function, but please share if you've already done something similar.

Update I want to return nested-dictionary

Dictionary<string, List<SomeType>> GetKeyPairValues()
{
  // get nested dictionary from this.myDict
}

Upvotes: 0

Views: 3601

Answers (4)

cuongle
cuongle

Reputation: 75306

You need to use GroupBy to group by Key then merge all list with the same key:

 Dictionary<string, List<SomeType>> GetKeyPairValues()
 {
      return dic.Values.SelectMany(d => d)
                       .GroupBy(p => p.Key)
                       .ToDictionary(g => g.Key, 
                                     g => g.SelectMany(pair => pair.Value)
                                           .ToList());
 }

Upvotes: 2

James
James

Reputation: 82096

What I want is to get nested dictionary

return myDict.Values.ToDictionary(x => x.Keys, x => x.Values);

Based on your comment, and looking at how complex the LINQ expression is going to have to be for this, why not just go for a basic for loop e.g.

Dictionary<string, List<SomeType>> GetKeyPairValues()
{
    foreach (var pair in dict)
    { 
        yield return pair.Value;
    }
}

It also might be more efficient than using LINQ.

Upvotes: 2

Kirill Bestemyanov
Kirill Bestemyanov

Reputation: 11964

Try this:

var dictionary = new Dictionary<string, Dictionary<string, List<int>>>();//initialize your source dictionary
var mergedDictionary = dictionary.SelectMany(d => d.Value).ToDictionary(k=>k.Key, k=>k.Value);

Update: use ToDictionary

Upvotes: 1

Rickard
Rickard

Reputation: 2335

Actually Dictionary<> implements multiple Values properties. If you use it through IDictionary<> you get a ICollection<TValue>

IDictionary<string, Dictionary<string, List<SomeType>>> dict = new Dictionary<string, Dictionary<string, List<SomeType>>>();
ICollection<Dictionary<string, List<SomeType>>> = dict.Values;

Upvotes: 0

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