Is there a simple way to print each element of an array?

Question

let x=[|15..20|]
let y=Array.map f x
printf "%O" y

Well, I got a type information.

Is there any way to print each element of "y" with delimiter of ",", while not having to use a for loop?

Answer 1

Either use String.Join in the System namespace or F# 'native':

let x = [| 15 .. 20 |]

printfn "%s" (System.String.Join(",", x))

x |> Seq.map string |> String.concat "," |> printfn "%s"

Answer 2

Using String.concat to concatenate the string with a separator is probably the best option in this case (because you do not want to have the separator at the end).

However, if you just wanted to print all elements, you can also use Array.iter:

let nums= [|15..20|]
Array.iter (fun x -> printfn "%O" x) nums    // Using function call
nums |> Array.iter (fun x -> printfn "%O" x) // Using the pipe 

Adding the separators in this case is harder, but possible using iteri:

nums |> Array.iteri (fun i x ->
  if i <> 0 then printf ", "
  printf "%O" x)