CODEWITHSUNDEEP
c#linq
aleczandru
aleczandru

Reputation: 5469

Joining two dictionaries

Hi I have two Dictionaries and I need to find a way to join them together.Here are the two dictionary types.

IDictionary<string, byte[]> dictionary1
IDictionary<IFileShareDocument, string> dictionary2

Out of this two dictionaries I have to create a third dictionary that will look like this

IDictionary<IFileShareDocument, byte[]> dictionary3

Both dictionaries have the exact same number of items and the string property of both them is the linking point.

What I would like is to be able to write something that would do somethign like this:

dictionary1.value join with dictionary2.key
where dictionary1.key == dictionary2.value

This statement should result in dictionary3.

Is there any way I can achieve this I can not seem to find a way to do this?

Upvotes: 1

Views: 1067

Answers (3)

Tim S.
Tim S.

Reputation: 56586

Here's a way to do it using the LINQ query syntax, with join (this compiles to roughly the same thing as @KingKing's solution):

IDictionary<IFileShareDocument, byte[]> dictionary3 =
    (from item1 in dictionary1
     join item2 in dictionary2 on item1.Key equals item2.Value
     select new { item2.Key, item1.Value })
         .ToDictionary(x => x.Key, x => x.Value);

Note that the above is greatly preferred to this example using from and where, because it is more efficient. I'm including this here because if you're like me (more familiar with SQL, which would convert something like this to a join automatically), this poor way might be the first one that comes to mind:

IDictionary<IFileShareDocument, byte[]> dictionary3 =
    (from item1 in dictionary1
     from item2 in dictionary2
     where item1.Key == item2.Value
     select new { item2.Key, item1.Value })
         .ToDictionary(x => x.Key, x => x.Value);

Upvotes: 2

Enigmativity
Enigmativity

Reputation: 117175

Would this work for you?

var result =
    dictionary2
        .ToDictionary(x => x.Key, x => dictionary1[x.Value]);

Upvotes: 2

King King
King King

Reputation: 63387

var dictionary3 =
    dictionary1
        .Join(dictionary2, x => x.Key, x => x.Value, (x, y) => new { x, y })
        .ToDictionary(a => a.y.Key, a => a.x.Value);

Upvotes: 5

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