[Haskell-cafe] avoid to print empty string

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