[Haskell-beginners] System.Random

[Thomas Friedrich]

Hi everyone,

Using random numbers in Haskell is not entirely trivial (at least, still 
not for me) and again I am bagging my head against the Gen-Monad.  I'd 
like to write a kind of bootstrap function

sample :: Int -> [a] -> [a]
sample n xs = ...

that samples uniformly n elements from the list xs.  I am not sure how 
to go about this.  Would you try something like

sample1 :: StdGen -> Int -> [a] -> [a]

and later use this in an IO Monad, something along the lines of:  do {g 
<- mkStdGen; return $ sample g n xs}, or would you write it like

sample2 :: Int -> [a] -> Gen [a]

and then use a function from QuickCheck like `generate` to get your samples?

You see, I don't even know how to start thinking about the problem.

If anyone got an idea, I'd be pleased if you could help me.

Cheers,
Thomas