Hello. In my journey to learning Elixir, I gave myself the task of implementing an algorithm that obtains the intersection of two MapSets without using the built-in MapSet.intersection/2 function: a = MapSet.new([3, 3, 3, 2, 2, 1]) b = MapSet.new([3, 4, 5]) # => Expected result #MapSet<[3]> def…

It’s a quirk of Elixir that most of the Enum functions that return collections return lists rather than the type you start with–it has to do with lack of typing and no good way to definitely determine what the return type should be. You’re looking for Enum.into to turn your list into a map. As for …

Hi @sribe . Thanks so much for your answer. [image] sribe: It’s a quirk of Elixir that most of the Enum functions that return collections return lists rather than the type you start with I did not know that. I will pay close attention to this caveat. [image] sribe: my only suggestion wou…

[image] Andres: I would greatly appreciate an example of the optimization you suggest. :wink: I think that @sribe is suggesting to choose which collection you iterate through (a or b in your code) depending on which one is the smallest. You can in fact minimize the number of comparisons neces…

Hello @lucaong . Thank you very much for your explanation. Very clear and concise. :smiley:

[image] Andres: I would greatly appreciate an example of the optimization you suggest. :wink: The source is a good place to start: https://github.com/elixir-lang/elixir/blob/98485daab0a9f3ac2d7809d38f5e57cd73cb22ac/lib/elixir/lib/map_set.ex#L247-L250

[image] sribe: It’s a quirk of Elixir that most of the Enum functions that return collections return lists rather than the type you start with–it has to do with lack of typing and no good way to definitely determine what the return type should be. It’s not so much “lack of types”, but more th…

Hi @al2o3cr [image] al2o3cr: The source is a good place to start: Definitely. Thanks so much for your answer. :smiley:

[image] LostKobrakai: Not keeping the shape of data was a conscious decision, which is explained (in a sadly little hidden place) here: Collectable — Elixir v1.20.2 Thank you very much for your clarification and for sharing this link.