Use the rweibull
function. Btw, do you want just one simulated value per parameter pair?
Anyhow, this should do it for nobs
number of observations. You can choose n=1 as well.
simulations <- mapply(rweibull, shapes, scales, MoreArgs=list(n=nobs))
where shapes
is your vector containing the shape parameters, and similarly scales
is the vector containing the scale parameter values.