F# Dojo Digits Recognizer

dojo-digits-recognizer.fsx

type Image = int []
type Sample = { Label:int; Pixels:Image }

let csvToRecords (lines:string[]) =
  lines.[1..]
  |> Array.Parallel.map (fun x -> x.Split(','))
  |> Array.Parallel.map (Array.map int)
  |> Array.Parallel.map (fun x -> {Label = x.[0]; Pixels = x.[1..]})

let distance (sample1:Image) (sample2:Image) =
  Array.map2 (fun x y -> pown (x - y) 2) sample1 sample2
  |> Array.sum
  |> float
  |> sqrt

let classify (examples:Sample[]) (unknown:Sample) =
  examples
  |> Array.sortBy (fun x -> distance unknown.Pixels x.Pixels)
  |> fun x -> x.[..10]
  |> Seq.groupBy (fun x -> x.Label)
  |> Seq.maxBy (fun (x, _) -> x)
  |> fun (x, _) -> x

let validations = File.ReadAllLines("validationsample.csv") |> csvToRecords
let examples = File.ReadAllLines("trainingsample.csv") |> csvToRecords

validations
  |> Array.averageBy (fun x -> if x.Label = classify examples x then 1.0 else 0.0)