Group totals in F# - easy with sequences, is it possible with lists?

Question

Given a sequence of a group id/value tuples, it was easy to calculate group totals (pretty much the same way I would do it with C# and LINQ):

let items = [\"g1\"         


        

Answer 1

While there's nothing wrong with gradbot's solution, I'd just keep it simple and use Seq.toList to convert sequences back to lists when desired. So you could rewrite your definition as:

let groupsums =
    items
    |> Seq.groupBy fst
    |> Seq.toList
    |> List.map (fun (_,s) -> Seq.sumBy snd s)