# Random doubles

**Marcin 'Qrczak' Kowalczyk
**
qrczak@knm.org.pl

*14 Feb 2001 18:36:15 GMT*

Wed, 14 Feb 2001 16:25:04 +0000, andrew@andrewcooke.free-online.co.uk <andrew@andrewcooke.free-online.co.uk> pisze:
>* Could someone please post a fragment of code that builds a list of
*>* random Doubles using RandomIO (recursively, please, although an
*>* example of using the interface that gives lists of random values
*>* directly would also be interesting)?
*
Doubles from which range? Assuming (0,1) and that the Int means the
length of the list:
import Random
import Monad
rands1:: Int -> IO [Double]
rands1 0 = return []
rands1 n = do
x <- randomIO
rest <- rands1 (n-1)
return (x:rest)
rands2:: Int -> IO [Double]
rands2 0 = return []
rands2 n = liftM2 (:) randomIO (rands1 (n-1))
rands3:: Int -> IO [Double]
rands3 n = sequence (replicate n randomIO)
rands4:: Int -> IO [Double]
rands4 n = do
g <- newStdGen
return (take n (randoms g))
--
__("< Marcin Kowalczyk * qrczak@knm.org.pl http://qrczak.ids.net.pl/
\__/
^^ SYGNATURA ZASTĘPCZA
QRCZAK