[R] without a loop

[Gabor Grothendieck]

On 6/7/05, Omar Lakkis <uofiowa at gmail.com> wrote:
> tmp <- c(-1,NA,NA,1,1,NA,NA,1)
> 
> without using a loop, how can I replace all NAs in the list above with
> the previous none NA value in the list?

This is known as last occurrence carried forward (LOCF) and
is implemented in both the 'zoo' and 'its' packages, e.g.

library(zoo)
na.locf(tmp)