[R] Creating a new vector ( another problem)
Peter Dalgaard
p.dalgaard at biostat.ku.dk
Mon Nov 20 16:36:29 CET 2006
Amir Safari <amsa36060 at yahoo.com> writes:
> Suppose we are interested for generating a new vector ( x ) from a current vector (y) of length 1000 so that x includes the sum of every 5 values in y respectively from the first to the end of length y. The same length of y for x is desired, so that other 4 positions (indices) in x are filled out with NA.
>
> For generating such a new vector, I have no idea. I tried in some ways but all were wrong and therefore I do not want to confuse you.
> How could such a purpose be coded?
> Please help me with any idea. Thank you so much for help.
> Amir Safari
Here's one idea (for the case 1000 == 20 ...):
y <- rpois(20, 3)
s <- colSums(matrix(y,nrow=5))
r <- rep(NA, 20)
r[(1:20) %% 5 == 0] <- s
cbind(y,r)
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