Help with F#, filtering a list using two disjunct conditions?

[GodlessAstronomer]

I'm trying to learn F# and I have a very simple problem I want to solve - I have a list of integers and I want to filter it so that only numbers which meet at least one of two conditions remain. This seems really freaking simple but I can't figure out how to do it in F#.

Let's say I want to keep a list of the numbers that are evenly divisible by either 2 or 3. In C# or similar I'd write

List<int> filterList(List<int> list) {
  List<int> result = new ArrayList<int>();
  foreach (int i in list)
    if (i % 2 == 0 || i % 3 == 0) result.add(i);
  return result;
}

and I'm thinking the F# code should look something like

let filterList list = List.filter (fun n%3=0 || n%2=0) list

but obviously something is wrong with the syntax and I find F# error messages rather cryptic. Any help would be appreciated.

 

[TheRickRoller]

let filterList list = List.filter (fun n%3=0 || n%2=0) list

Hey friend, I am learning F# right now too. When creating a lambda, you need to use -> like this:

let filterList list = List.filter (fun n -> n%3=0 || n%2=0) list

Otherwise you're on the right track.

 

[GodlessAstronomer]

Heh thanks, I knew if would be something simple. Thanks a lot dude! Are you using a book to learn F#? I picked up Real World Functional Programming with Examples in F# and C# and it's pretty good but I don't think there's enough focus on the basics of functional programming. I'm only about 1/5th into the book though so it may turn around.

 

[TheRickRoller]

I'm not using a book at the moment, just browsing the MSDN and various other sites (mainly Stack Overflow) when I want to find something. Theres a lot of good links and books in this post: http://stackoverflow.com/questions/734525/getting-started-with-f, in particular the wiki books link would be a good companion to your book, and Syme's blog is a good read.