Personal tools

99 questions/Solutions/15

From HaskellWiki

< 99 questions | Solutions(Difference between revisions)
Jump to: navigation, search
(added solution using list monad)
Line 15: Line 15:
 
repli :: [a] -> Int -> [a]
 
repli :: [a] -> Int -> [a]
 
repli xs n = concatMap (take n . repeat) xs
 
repli xs n = concatMap (take n . repeat) xs
  +
</haskell>
  +
  +
or, using the list monad:
  +
<haskell>
  +
repli :: [a] -> Int -> [a]
  +
repli xs n = xs >>= replicate n
 
</haskell>
 
</haskell>

Revision as of 14:21, 5 August 2011

(**) Replicate the elements of a list a given number of times.

repli :: [a] -> Int -> [a]
repli xs n = concatMap (replicate n) xs

or, in Pointfree style:

repli = flip $ concatMap . replicate
alternatively, without using the
replicate
function:
repli :: [a] -> Int -> [a]
repli xs n = concatMap (take n . repeat) xs

or, using the list monad:

repli :: [a] -> Int -> [a]
repli xs n = xs >>= replicate n