f#

I have the following function in F#: let randomCh () = let random = Random() alph.Chars (random.Next (alph.Length - 1)); This function returns same value each time. I had same problem in C#, and solution very simple: create just one Random object like this: var rnd = new Random(); for (int i = 0; i < 10; i++) Console.WriteLine(rnd.Next(10)); How can I reach same behaviour in F#: get each time random value? Well your C# code doesn't define a function whereas your F# does; you could have the same problem in C#. You should either refactor your random definition out of the randomCh function, or

I am learning F#. I am trying to convert a Map<string, seq<DateTime * float>> to a Deedle dataframe ( http://bluemountaincapital.github.io/Deedle/tutorial.html#creating ). I have prapared the following code: let folderFnct (aFrame:Frame) colName datesAndValues = let newSerie = Series(Seq.map (fun x -> fst x) datesAndValues, Seq.map (fun y -> snd y) datesAndValues) let newFrame = aFrame.Join([colName], [newSerie], kind=JoinKind.Inner) newFrame let mapToDeedleFrame myMap frame = Map.fold ( fun s ticker datesAndValues -> folderFnct s ticker datesAndValues) frame myMap mapToDeedleFrame folds the

I'm attempting to implement a fold over a discriminated union. The DU is called Expr, and represents a program expression, and is often recursive. I'm attempting to write a fold that accumulates the result of an operation over the Exprs recursively. Below is my attempt to write the fold. let rec foldProceduralExpr (folder : 's -> Expr list -> 's) (state : 's) (expr : Expr) : 's = let children = match expr with | Series s -> s.SerExprs | Lambda l -> [l.LamBody; l.LamPre; l.LamPost] | Attempt a -> a.AttemptBody :: List.map (fun ab -> ab.ABBody) a.AttemptBranches | Let l -> l.LetBody :: List

I have the following code in a Test.fs file: namespace Testing module test1 = let Run = printfn "Test1" module test2 = let Run = printfn "Test2" In my Program.fs I am calling: [<EntryPoint>] let main argv = let sw = Stopwatch.StartNew() printfn "%A" Testing.test1.Run sw.Stop() printfn "Problem took %d minutes, %d seconds, and %d milliseconds" sw.Elapsed.Minutes sw.Elapsed.Seconds sw.Elapsed.Milliseconds let s = Console.ReadLine() 0 // return an integer exit code This outputs Test1 Test2 Why is Test2 being outputting even though I am only calling Test1.Run ? test1.Run is not a function, it is a

I have a simple tree, defined thusly: type BspTree = | Node of Rect * BspTree * BspTree | Null I can get a collection of leaf nodes (rooms in my tree "dungeon") like this, and it seems to work: let isRoom = function | Node(_, Null, Null) -> true | _ -> false let rec getRooms dungeon = if isRoom dungeon then seq { yield dungeon } else match dungeon with | Node(_, left, right) -> seq { for r in getRooms left -> r for r in getRooms right -> r } | Null -> Seq.empty But now I'm trying to get sister leaf node rooms so I can connect them with corridors, and I'm failing miserably (as I often do). Here