[R] Creating a new vector ( another problem)

[Peter Dalgaard]

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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