// Learn more about F# at http://fsharp.net

// See the 'F# Tutorial' project for more help.

//goal: every odd digit of a sin

let sin = "123 456 789"

let c = sin.[0]

let a = sin.ToCharArray()

let b = Seq.toList a

let d = Seq.toList sin

let c1:char = 'a'

let c2:char = 'b'

let nospace =

//List.filter (fun c -> c != ' ')

//List.filter (fun c -> not (c = ' ')) //huh.. char doesn't support !=

List.filter (fun c -> c = ' ' |> not) //lol

//let include c = function

// | [x] -> true

// | x:remainder -> x

let rec oddeven = function

| [] -> []

| [x] -> [x]

| x1::x2::xs ->

let nexty = oddeven xs

x1::nexty

//open System; let x = "abcdef01234567" |> Seq.take 5 |> String.Concat;;

let daStuff r:string = /// <-- methinks I meant to say (r:string) at the time...

let o =

r |>

Seq.toList |>

nospace |>

oddeven |>

List.toArray |>

(fun charArray -> new System.String(charArray))

o

//took a long break

let makeString (a: char list) =

List.fold (fun stringResultState char -> stringResultState + (string char) ) "" a

let makeString2 (a: char list) =

let seperator = ""

a |> List.map string |> String.concat seperator

let cheat (a: char list) =

let sb = new System.Text.StringBuilder()

a |> List.iter (fun c -> sb.Append(c) |> ignore)

sb.ToString()

let daNewStuff s =

s

|> Seq.toList

|> nospace

|> oddeven

|> makeString

let asIsInOne s =

s

|> Seq.toList

|> List.filter (fun ch -> not(ch = ' '))

|> oddeven

|> (fun f -> f)

|> List.map string

|> String.concat ""

let inOne s = //you can do it all without a list

s

|> Seq.filter (fun char -> not (char = ' '))

|> Seq.mapi (fun index element -> (element, index)) //tuple!

|> Seq.filter (fun (element, index) -> index % 2 = 0)

//|> Seq.map fst

//|> Seq.map string

|> Seq.map (fst >> string)

|> String.concat ""

//or

//|> Seq.fold (fun stringResultState char -> stringResultState + (string (fst char))) ""

//|> Seq.fold (fun stringResultState tuple -> tuple |> fst |> string |> (+) stringResultState ) ""

[<EntryPoint>]

let main argv =

printfn "args %A" argv

printfn "sin %A" sin

printfn "everyodd1 %A" (daNewStuff sin)

printfn "everyodd2 %A" (asIsInOne sin)

printfn "everyodd3 %A" (inOne sin)

if (System.Diagnostics.Debugger.IsAttached) then

System.Console.ReadKey() |> ignore

0 // return an integer exit code