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Multiplication tables: Difference between revisions

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Multiplication tables (view source)

Revision as of 12:55, 19 December 2016

32 bytes added ,  7 years ago
→‎{{header|Haskell}}: Switched core type from [Int] to Maybe Int
(→‎{{header|Haskell}}: Switched core type from [Int] to Maybe Int)
Line 2,254:
Or, making do without imports beyond the Prelude, and separating data from formatting:
 
<lang Haskell>multTable :: Int -> [[[Maybe Int]]]
multTable n = (\x -> [x] : [] : (
(\yx -> if y <Just x then [] else [x: *Nothing y]): (
(\y -> if y < x then Nothing else Just (x * <$> rangey))
<$> range))
where <$> range = [1..n]
where range = [1..n]
 
tableString :: [[[Maybe Int]]] -> String
tableString tbl = unlines $ (concat . (fmt <$>)) <$> tbl
unlines $ (concat . (fmt <$>)) <$> tbl
where▼
pad = " "▼
fmt [ ] = pad▼
fmt [e] = drop (length s) (pad ++ s)▼
where
pad s = show" e"
▲ fmt [ ]Nothing = pad
▲ fmt [e](Just n) = drop (length s) (pad ++ s)
▲ where
▲ pad = " s = show "n
 
main :: IO ()
Hout
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