import Data.List
import System.IO
import System.Random

rint = show `fmap` (randomRIO (0,100) :: IO Int)

dump cols rows name = do
  h <- openFile name WriteMode
  sequence_ . take rows . repeat $ do
    cs <- sequence . take cols . repeat $ rint
    hPutStrLn h . concat . intersperse "," $ cs
  hClose h

main = dump 1000 10000 "dump.csv"