Read two integers in the same line as tuple in f#

Question

I'm trying to read two integers which are going to be taken as input from the same line. My attempt so far:

let separator: char = 
    ' '
Console.ReadLine().Split separator
|> Array.map Convert.ToInt32

But this returns a two-element array and I have to access the individual indices to access the integers. Ideally, what I would like is the following:

let (a, b) =
    Console.ReadLine().Split separator
    |> Array.map Convert.ToInt32
    |> (some magic to convert the two element array to a tuple)

How can I do that?

Assuming you don't want to hardcode the number of integers, you might be able to adapt [How can i convert between F# List and F# Tuple?](https://stackoverflow.com/q/2920094/3744182) to your needs. — dbc, Dec 06 '20 at 17:09
If you use [F#+](https://github.com/fsprojects/FSharpPlus) you can do `let (a, b) = sscanf "%i %i" (Console.ReadLine ())` — Gus, Dec 06 '20 at 23:09

score 2 · Accepted Answer · answered Dec 06 '20 at 17:14

I'm afraid there's no magic. You have to explicitly convert into a tuple

let a, b =
    Console.ReadLine().Split separator
    |> Array.map int
    |> (fun arr -> arr.[0], arr.[1])

Edit: you can use reflection as @dbc suggested but that's slow and probably overkill for what you're doing.

1 Answers1