Re: [R] applying a function in list of indexed elements of a vector:

Your code for iy doesn't work as providedI'll assume you meant this instead: iy <- list(c(1, 2),c(1, 2), c(1, 2, 3, 4), c(2, 3, 5), c(4), c(5, 6, 7), c(7, 8, 9)) Then sapply(iy, function(x) sum(Y1[x])) Michael On Sat, Mar 10, 2012 at 5:01 PM, aldi wrote: > Hi, > > I have a vector > Y1 <-c

[R] applying a function in list of indexed elements of a vector:

Hi, I have a vector Y1 <-c(8, 11, 7, 5, 6, 3, 6, 3, 3) and an index iy <-c(c(1, 2),c(1 2), c(1, 2, 3, 4), c(2, 3, 5), c(4), c(5, 6, 7), c(7, 8, 9)) how can I produce the mean, or the sum of the elements specified in the index iy from the vector Y1? expecting something like this for th