Reading numbers from console until input isn't a number

Question

I want to read N numbers (Nmax = 100) from console into a list. N is not known, but the first input that is not a number may break the reading process... However the solution should be as simple as possible, so I just read 100 lines:

let numbers = [1..100]
 |> List.map (fun x -> Int32.TryParse(Console.ReadLine())) 
 |> List.filter (fun (isNum, num) -> isNum)
 |> List.map (fun (isNum, num) -> num)

Is there a simpler (less code) solution?

Answer 1

Your code does not read numbers from the "console until input isn't a number", but reads 100 inputs strings from the console and returns those that can be converted to integers.

If you want to read numbers from the console "until input isn't a number", you could do something like this:

let numbers1 max = seq {for x in 1..max do yield Int32.TryParse(Console.ReadLine()) }
 |> Seq.takeWhile (fun (b, x) -> b) 
 |> Seq.map (fun (b, x) -> x)

or

let numbers2 max = seq {for x in 1..max do yield Int32.TryParse(Console.ReadLine()) }
 |> Seq.takeWhile (fun (b, x) -> b) 
 |> Seq.map (fun (b, x) -> x)
 |> Seq.toList

if you want to defer the return of each input to after the last valid input has been entered.

• JanDotNet: Seq.takeWhile makes it! I hoped there is an even shorter solution... but that one work fine, thanks :)