[Haskell-beginners] merge two files in to one file

[kolli kolli]

thanks a lot...

On Tue, Oct 4, 2011 at 7:24 PM, Erik de Castro Lopo <mle+hs at mega-nerd.com>wrote:

> kolli kolli wrote:
>
> > all the lines of first file followed by all the lines of second file
>
> Well, it can be as simple as:
>
>    main :: IO ()
>    main = do
>        data1 <- readFile "firstfile"
>        data2 <- readFile "secondfile"
>        writeFile "output" (data1 ++ data2)
>
> which should work fine for text files of arbitrary length. It won't
> however work for binary files (due to text encoding issues). For that
> try something like:
>
>    import qualified Data.ByteString.Lazy as BSL
>
>    main :: IO ()
>    main = do
>        data1 <- BSL.readFile "firstfile"
>        data2 <- BSL.readFile "secondfile"
>        BSL.writeFile "output" (BSL.concat [data1, data2])
>
> In both cases, Haskell's lazy evaluation means that the program does
> not need to read in the whole of each file, but will read both files
> in chunks as well as writing the output file in chunks.
>
> HTH,
> Erik
> --
> ----------------------------------------------------------------------
> Erik de Castro Lopo
> http://www.mega-nerd.com/
>
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