Evaluate an R expression with a temporarily set random set
Evaluate an R expression with a temporarily set random set.
withSeed(expr, seed, ..., substitute=TRUE, envir=parent.frame())
expr |
The R expression to be evaluated. |
seed, ... |
Arguments passed to |
substitute |
If |
envir |
The |
Upon exit (also on errors), this function will restore
.Random.seed in the global environment to the value
it had upon entry. If it did not exist, it will be removed.
Returns the results of the expression evaluated.
Henrik Bengtsson
Internally, set.seed() is used to set the random seed.
# Generate a random number
y0 <- runif(1)
print(y0)
# Generate a random number using the same seed over and over
yp <- NULL
for (ii in 1:10) {
y <- withSeed({
runif(1)
}, seed=0x42)
print(y)
# Assert identical
if (!is.null(yp)) stopifnot(identical(y, yp))
yp <- y
}
# Generate a random number
y <- runif(1)
print(y)Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.