[Haskell-cafe] Random Numbers for the beginner ?
Koji Nakahara
yu- at div.club.ne.jp
Tue Jul 6 17:48:12 EDT 2004
On Tue, 06 Jul 2004 19:09:53 +0000
"Crypt Master" <cryptmaster at hotmail.com> wrote:
> So I added RollDice to my module. This doesnt error, but it doesnt return
> anything except blank spaces:
>
> HasGal> rollDice
>
> HasGal>
>
> Integers or nums should automatically have show correct? So this should show
> me something ?
rollDice is an action of type IO Int, not a number of type Int.
Try
Main> do n <- rollDice; print n
> Ultimatly I want to get randomRs infinite list working so I can build
>
> randNums = (take (length popList) [1..])
>
> where the length of pop list is how many random numbers I want. My code
> works as it, just need to replace [1..] with some random numbers.
Example:
----
import Random
rollDices :: RandomGen g => g -> [Int]
rollDices = randomRs (1, 6)
randNumInfSeq :: [Int]
randNumInfSeq = rollDices (mkStdGen 0)
---
Main> do g <- getStdGen; let randNums = take 20 $ rollDices g in print randNums
[5,3,3,5,1,6,5,6,2,2,6,2,3,6,2,5,2,6,1,4]
Main> print $ take 20 $ randNumInfSeq
[6,6,4,1,5,2,4,2,2,1,6,5,1,5,3,2,3,4,4,1]
Hope it helps,
Koji Nakahara
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