On 8/3/2006 9:17 PM, Matthew Wilson wrote: > I'm studying R in my free time. I want to build a vector where each > element is equal to the element before it in the sequence plus some > random tweak. > > In python, I would write: > > vec = [100] * 50 # make a 50-element list with each element set to 100 > from random import randint > for i, v in enumerate(vec): > if i is not 0: # if we're not on the first element > vec[i] = vec[i-1] + randint(-2, 2) > > I suspect R has some fancier way of doing this. How to?
Assuming randint(-2, 2) gives a value uniform on (-2, 2) a quick way to do what you want is vec <- 100 + c(0, cumsum(runif(49, -2, 2))) Duncan Murdoch ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.