Difference between revisions of "Haskell Quiz/DayRange/Solution Jethr0"
< Haskell Quiz | DayRange
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m (added example) |
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<haskell> |
<haskell> |
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+ | -- > dayRange [1,2,3,6,7] |
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+ | -- "Mon-Wed, Sat, Sun" |
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dayRange = sepComma . map range . map (map toWeekday) . groupAscend . sort |
dayRange = sepComma . map range . map (map toWeekday) . groupAscend . sort |
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where sepComma = concat . intersperse ", " |
where sepComma = concat . intersperse ", " |
Revision as of 17:54, 16 December 2006
-- > dayRange [1,2,3,6,7]
-- "Mon-Wed, Sat, Sun"
dayRange = sepComma . map range . map (map toWeekday) . groupAscend . sort
where sepComma = concat . intersperse ", "
toWeekday x = weekdays!!(x-1)
range xs | length xs < 3 = sepComma xs
| otherwise = head xs ++ "-" ++ last xs
weekdays = ["Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun"]
groupAscend (x:xs) = together $ foldl ascend ([],[x]) xs
where ascend (done,curr) e = if e == (last curr)+1 then (done, curr++[e])
else (done++[curr], [e])
together (a,b) = a++[b]