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myButLast'''' = head . tail . reverse
 
myButLast'''' = head . tail . reverse
myButLast''''' = last . init
 
 
</haskell>
 
</haskell>
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[[Category:Programming exercise spoilers]]

Revision as of 19:36, 18 January 2014

(*) Find the last but one element of a list.

myButLast :: [a] -> a
myButLast = last . init
 
myButLast' x = reverse x !! 1
 
myButLast'' [x,_]  = x
myButLast'' (_:xs) = myButLast'' xs
 
myButLast''' (x:(_:[])) = x
myButLast''' (_:xs) = myButLast''' xs
 
myButLast'''' = head . tail . reverse