Difference between revisions of "Programming performance/ArthurVanLeeuwen Haskell"
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(comment about potential bug) |
Tomjaguarpaw (talk | contribs) (Deleting page that hasn't been edited for over 10 years) |
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| − | Didn't feel like thinking at all, so this is a trivial recursive solution. |
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| − | === Code === |
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| − | <haskell> |
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| − | main = do xs <- getContents |
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| − | let cashheld = runStrategy 10000 . reverse . getDays . filter (\l -> head l /= '#') . filter (not . null) $ lines xs |
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| − | putStrLn $ "Cash held: " ++ show cashheld |
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| − | getDays :: [String] -> [(String,Double,Double,Double,Double,Integer,Double)] |
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| − | getDays = map getDay |
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| − | getDay :: String -> (String,Double,Double,Double,Double,Integer,Double) |
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| − | getDay s = getDay' $ words s |
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| − | where getDay' [date,open,high,low,close,volume,adjustedclose] = (date,read open,read high,read low,read close,read volume,read adjustedclose) |
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| − | runStrategy cash lines = runStrategy' cash lines [] |
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| − | runStrategy' cash lines shares = |
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| − | case lines of |
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| − | (c1:c2:_) -> if (closing c2 - closing c1) / closing c1 < - 0.03 then |
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| − | runStrategy' (cash * 0.9) (tail lines) ((((cash * 0.1) / closing c2), closing c2): shares) |
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| − | else if not . null $ shares then |
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| − | if (closing c2 - (snd . head $ shares)) / (snd . head $ shares) > 0.06 then |
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| − | runStrategy' (cash + (fst . head $ shares) * closing c2) (tail lines) (tail shares) |
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| − | else runStrategy' cash (tail lines) shares |
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| − | else runStrategy' cash (tail lines) shares |
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| − | [c1] -> cash + sellOff (closing c1) shares |
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| − | [] -> cash |
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| − | sellOff price shares = sum . map (* price) . map fst $ shares |
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| − | closing (date,open,high,low,close,volume,adjustedclose) = close |
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| − | </haskell> |
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| − | * '''Bug/Question''': This solution will only perform one sale per day, even if multiple sales qualify, right? If recursion after a sale used lines instead of tail lines, then multiple sales could occur. [[User:Newsham|Newsham]] 18:08, 8 March 2007 (UTC) |
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