Simple KNN

simpleKNN

let distance v1 v2 = 
    Array.zip v1 v2
    |> Array.fold (fun sum e -> sum + pown (fst e - snd e) 2) 0.0
    |> sqrt

let classify subject dataSet labels k = 
    dataSet
    |> Array.map (fun row -> distance row subject)
    |> Array.zip labels
    |> Array.sortBy snd
    |> Array.toSeq
    |> Seq.take k
    |> Seq.groupBy fst
    |> Seq.maxBy (fun g -> Seq.length (snd g))

let createDataSet =
    [| [| 1.0; 0.9 |]
       [| 0.8; 1.0 |]
       [| 0.8; 0.9 |]
       [| 0.0; 0.1 |]
       [| 0.3; 0.0 |]
       [| 0.1; 0.1 |] |],
    [| "A"; "A"; "A"; "B"; "B"; "B" |]

let data, labels = createDataSet

classify [| 0.2; 0.4 |] data labels 3
classify [| 0.7; 0.4 |] data labels 3