Question

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
}

Answer 1

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());
 }