i have this in a Monad IO:

 forM_ fltrdNamesBDs $ \(name,bdSidonie,bdWDS) ->
          if (bdWDS /= bdSidonie)
          then
             putStrLn $  name ++ " " ++ (show (bdSidonie :: Maybe Float)) ++ " " ++ show (bdWDS :: Maybe Float) ++ " " ++ show (bdWDS == bdSidonie)
          else
             putStr ""

is there a way to remove the silly putStr "" that output an empty string, i tried with when.... but as when return Nothing in case of False it fails to compile