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Practical Usage of Tuple in C#

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Introduction of ‘Tuple’ in .NET Framework 4.0, really filled in a missing piece in C#. Apart from giving us the ability to interoperate with functional languages like F# or Python/Ruby, It does offer the convenience of heterogeneous collection which can take form of any class or structure that you would have created otherwise.

In C#, I feel Tuple syntax is still in its early stages and I am hopeful it will take more friendly syntax in next iterations. I have been explaining the concept of Tuple quite a while now during my presentations. Some of the questions that people ask me during my presentations are:

    1. Do we really need Tuple?
    2. What is the practical use of Tuple?

My answer to these questions are as below:

    1. YES – we need Tuple to talk to F# or Python. Let us assume a scenario where you have some code written in Python and it used tuples there. As a developer, you want to use the code in C#.  What data type you will use to map to the Python’s ‘tuple’. The representation was entirely missing from C#/.NET.  So – to fill this gap, the tuple was launched.
    2. Here are couple of scenarios where it can be used:
      1. Assume you have to return multiple values from a function call that are unrelated or of different types. You could still achieve it by creating a custom class/struct but Tuple will give you instant solution and with much convenience. Especially – if the values are unrelated you wouldn’t want to create a custom type just for the sake of returning few values at once.
      2. All the places where you felt limited by using the KeyValuePair class.

Comments

  • Anonymous
    May 21, 2011
    The other scenario where you can use this is to avoid anonymous types. weblogs.asp.net/.../tuple-net-4-0-new-feature.aspx Thanks, Arun

  • Anonymous
    May 21, 2011
    Thanks Arun for pointing this. You post is really nice.  You're correct - Avoiding Anonymous Types is another usage for Tuples.

  • Anonymous
    May 21, 2011
    Personally I don't like Tuples for day-to-day programming. For interoperability that's fine, but one of C#'s best design principles (and, I suspect the reason it took so long to wedge Tuples into the feature set) is it's type-safe and descriptive approach to objects. With Tuples, on the other hand, you can basically make a "random bag" which contains random objects. When I write my code to receive a Tuple<string, string, int> what does that mean? Unless someone tells me the only way to figure it out is to trace through the code that sent it to me. Yuck!

  • Anonymous
    May 23, 2011
    I'm with Mike. I feel dirty every time I use Tuple. Item1, 2, and 3. What ARE they?

  • Anonymous
    May 23, 2011
    I am also not a big fan of the syntax and the pattern matching which is in-built with Tuple in C# at this point. However - as I said in this post, it is still very nascent. I am hopeful it will change as the concept evolves further.

  • Anonymous
    December 06, 2011
    I have found a use for Tuples to eliminate methods that have too many parameters. For example, when you build a class that queries the database based on several search parameters, instead of having a method that takes 5 parameters, have it take a tuple that holds those values so you still only pass in one object. Helps make the code readable as long as you use metadata to help make the purpose clear.