Random Number with a predefined width in F#

Question

How can I defined the width of a random number?

let randomNumber = System.Random()
let randomBarcodePart2 = randomNumber.Next(**000000, 999999**)

I have this now, but is it possible to generate a random number, where we only defined the width.

Like this:

let randomBarcodePart2 = randomNumber.Next(6)

Answer 1

simple example with printf:

let t = randomNumber.Next(0,999999)
printfn "%07i" t

Answer 2

You can do this with a type extension:

type System.Random with
    member x.Width w =
        x.Next(0, pown 10 w - 1)
        |> sprintf "%0*d" w

Here's a few outputs

Random().Width 6;;
val it : string = "985326"

Random().Width 9;;
val it : string = "803426947"

Random().Width 1;;
val it : string = "6"