12 lines
269 B
Forth
12 lines
269 B
Forth
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open System
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let ld x = Math.Log x / Math.Log 2.
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let entropy (s : string) =
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let n = float s.Length
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Seq.groupBy id s
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|> Seq.map (fun (_, vals) -> float (Seq.length vals) / n)
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|> Seq.fold (fun e p -> e - p * ld p) 0.
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printfn "%f" (entropy "1223334444")
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