Is there a data structure that holds sets of data in .NET?

Question

I'm looking for a data structure similar to a dictionary that returns the set of all related items to a key.

For example, I would use it like this:

var data = new FancyDataStructure();

data.Add(new string[] {"Elizabeth", "Liz", "Betty"});
data.Add(new string[] {"Bob", "Robert", "Rob"});

string[] alternateNames1 = data["Betty"];
string[] alternateNames2 = data["Liz"]

In this instance, alternateNames1 would be an array containing "Liz" and "Elizabeth", and alternateNames2 would be an array containing "Elizabeth" and "Betty."

I don't want to reinvent this, but I couldn't find any examples of such a structure.

Update

Thank you to those that have written back with suggestions. Many people have suggested using some version of Dictionary<string, IEnumerable<string>>. Currently I am using this approach, but it doesn't actually fulfill the requirement without being horribly difficult to maintain. Every value in every list needs to be able to function as a key to every other value ever added to it in a set.

Thus, given the following:

data.Add(new string[] {"Elizabeth", "Liz"}
data.Add(new string[] {"Liz", "Betty"}
alternates = data["Betty"];

I would expect alternates to now contain "Elizabeth," and "Liz."

It looks as though I might just have to build such a structure to suit my needs. Keep the ideas coming though!

Brian

Answer 1

Your problem sounds like it is really a graphing problem. Think of the names as nodes and membership in the set as the edges. From this standpoint, you would want a data structure that handles sparse graphs well, such as an adjacency list. This is, of course, similary to what you are already doing with a Dictionary<string, IEnumerable<string>> but thinking about it in this way might lead you to some helpful implementations and algorithms.