PRELUDE: add pivot

2014-11-29 05:09:58 +01:00 · 2014-11-29 05:09:58 +01:00 · 740c05fc1a
parent b5a56ea7b0
commit 740c05fc1a
1 changed files with 6 additions and 0 deletions
--- a/MyPrelude.hs
+++ b/MyPrelude.hs
@ -85,3 +85,9 @@ shiftM :: Int -> [a] -> [a]
 shiftM _ [] = []
 shiftM 0 xs = xs
 shiftM n xs = drop n xs ++ take n xs
+
+
+-- |Get the pivot of a list.
+pivot :: [a] -> Maybe a
+pivot [] = Nothing
+pivot xs = Just . (!!) xs . flip div 2 . length $ xs