Question

I am learning RX (Reactive Extensions), I tried to use some code samples from internet, the source code was in C#:

var input = Observable.Range(1, 100); 
input.Sum().Subscribe(x => Console.WriteLine("The Sum is {0}", x)); 

Since I don’t really “SPEAK” C#, so I want to use F# to do the same thing.
I download RX, and create a F# windows application, add reference to System.Reactive. My IDE is VS 2010 Ultimate, RX version is: 1.1.11111
Here is my code:

#light
open System
open System.Collections.Generic
open System.ComponentModel
open System.Linq
open System.Text
open System.Reactive
open System.Reactive.Linq

let input = Observable.Range(1, 100)
let x = input.Sum().Subscribe()
printfn "%A" x

The result should be 5050, as the sum of 1 to 100 is 5050. However, I can see only this:
System.Reactive.AutoDetachObserver`1[System.Int32]

Please let me know how I can see the result for 5050.
I hope the C# code will work in F# too. If not, please let me know what I can do.
Thanks and Happy New Year to you all!

Answer 1

The Subscribe method takes a function as its argument (x => foo is an anonymous function (lambda expression) in C#). So you should also call it with a function as its argument:

let input = Observable.Range(1, 100)
input.Sum().Subscribe(fun x -> printfn "%A" x)

Or

let input = Observable.Range(1, 100)
input.Sum().Subscribe(printfn "%A")