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Showing posts from February, 2011

Microsoft Azure Notebooks - Live code - F#, R, and Python

I was exploring Jupyter notebooks , that combines live code, markdown and data, through Microsoft's implementation, known as MS Azure Notebooks , putting together a small library of R and F# notebooks . As Microsoft's FAQ for the service describes it as : ...a multi-lingual REPL on steroids. This is a free service that provides Jupyter notebooks along with supporting packages for R, Python and F# as a service. This means you can just login and get going since no installation/setup is necessary. Typical usage includes schools/instruction, giving webinars, learning languages, sharing ideas, etc. Feel free to clone and comment... In R Azure Workbook for R - Memoisation and Vectorization Charting Correlation Matrices in R In F# Charnownes Constant in FSharp.ipynb Project Euler - Problems 18 and 67 - FSharp using Dynamic Programming

Project Euler - Problem #36

Description The decimal number, 585 = 1001001001 (binary), is palindromic in both bases. Find the sum of all numbers, less than one million, which are palindromic in base 10 and base 2. (Please note that the palindromic number, in either base, may not include leading zeros.) Solution (Improved) let isPalindromicBase2 (n:int) =      let forward = System.Convert.ToString(n,2) |> (fun c -> int c - int '0') |> Seq.toArray      let rev = Array.rev forward      if forward = rev then           true      else          false let reverse (s:string) = new string(s |> Seq.toArray |> Array.rev) let getPalindromesBase10 =      let base10Array = [|1..1000000|] |> Array.filter (fun x -> string x = reverse(string x))      let base02Array = base10Array |> Array.filter (fun x -> isPalindromicBase2  x)      Array.sum base02Array Solution (Original) let reverseToBinaryList (n:int) =      System.Convert.ToString(n,2)      |> (fun

Project Euler - Problem 34

Description 145 is a curious number, as 1! + 4! + 5! = 1 + 24 + 120 = 145. Find the sum of all numbers which are equal to the sum of the factorial of their digits. Note: as 1! = 1 and 2! = 2 are not sums they are not included. Solution let rec factorial n acc =      if n <= 1 then           acc      else           let newAcc = n * acc           factorial (n-1) newAcc let sumStr num =      let arrStr = num.ToString()      let len = String.length arrStr      let arrNum = Array.create len 0      for i=0 to len-1 do           let numTemp = System.Convert.ToInt32(arrStr.Chars(i).ToString())           arrNum.[i] <- factorial numTemp 1      Array.sum arrNum let sumTest = [3..99999]      |> (fun x -> if sumStr x = x then x else 0)      |> Array.sum