Project Euler in F# - Problem 1

re: Project Euler in F# - Problem 1

Bassam Abdul-Baki — Wed, 24 Oct 2007 21:47:36 GMT

Good idea. However, it didn't work, using the latest F# compiler, without adding a couple of in's for the two latter let's.

re: Project Euler in F# - Problem 1

ChrSmith — Wed, 24 Oct 2007 22:37:06 GMT

Thanks for the note! Yes, you can either add the 'in' keyword or declare #light at the top of the file. Don Syme has more information at:

http://blogs.msdn.com/dsyme/archive/2006/08/24/715626.aspx

I've updated my post.

re: Project Euler in F# - Problem 1

Bassam Abdul-Baki — Thu, 25 Oct 2007 03:36:21 GMT

My bad, first time using F# and the Euler relation intrigued me. Although, I could swear the script that F# generated had #light somewhere at the top. However, I'll try

re: Project Euler in F# - Problem 1

Robert Pickering — Fri, 26 Oct 2007 08:40:10 GMT

Hi Chris,

Nice effort, here are a couple of alterantive implmentations, which are a little shorter, first you could use a filter instead of adding the Mod35 predicated to your fold function:

let problem1 =

[1 .. 999]

|> Seq.filter (fun x -> x % 3 = 0 || x % 5 = 0)

|> Seq.fold (+) 0

printfn "Problem 1 = %d" problem1

Alternatively you can use step feature list comprehensions to remove any need to for filtering:

let problem1 =

[1 .. 3 .. 999] @ [1 .. 5 .. 999]

|> Seq.fold (+) 0

printfn "Problem 1 = %d" problem1

re: Project Euler in F# - Problem 1

code17 — Mon, 12 Nov 2007 18:30:12 GMT

try this:

Seq.fold1 (+) {for i in 1..999 when i%3*i%5=0 -> i}

Joining the F# team

Chris Smith's completely unique view — Tue, 20 Nov 2007 20:38:50 GMT

I'm please to announce that starting Monday I'll be joining the F# team as (currently) the only full-time tester. I'm super-excited about this for many reasons, but the biggest is knowing what an impact I'll have. Without a doubt F# will change the .Net

Week 2: My adventures with Euler #2

Joel Lanciaux — Wed, 06 Feb 2008 08:16:09 GMT

Week 2: My adventures with Euler #2

Robert Pickering is Incorrect

Michael de la Maza — Wed, 24 Dec 2008 16:25:21 GMT

Note that the second solution that Robert Pickering gives above is incorrect.

re: Project Euler in F# - Problem 1

Daniel Jackson — Mon, 02 Feb 2009 22:24:41 GMT

@ Michael de la Maza

The second solution Pickering has provided should begin the list comprehension from 0 rather than 1.

re: Project Euler in F# - Problem 1

Daniel Jackson — Mon, 02 Feb 2009 22:40:41 GMT

@ Michael de la Maza

Starting from 0 rather than 1 is more right, but only half way right. Appending the two lists [1 .. 3 .. 999] @ [1 .. 5 .. 999] also includes duplicate numbers that are divisable by both 3 and 5.

val it : int list

= [15; 30; 45; 60; 75; 90; 105; 120; 135; 150; 165; 180; 195; 210; 225; 240;

255; 270; 285; 300; 315; 330; 345; 360; 375; 390; 405; 420; 435; 450; 465;

480; 495; 510; 525; 540; 555; 570; 585; 600; 615; 630; 645; 660; 675; 690;

705; 720; 735; 750; 765; 780; 795; 810; 825; 840; 855; 870; 885; 900; 915;

930; 945; 960; 975; 990]