[R] Skip last NA's?

[Robert Lundqvist]

I wonder if anyone could help me find an expression for skipping the last
missing values in a vector? The kind of material I have is something like

x<-c(23,12,NA,23,24,21,NA,NA,NA)

I would like to skip the last NA's, but not the ones in between other
vallues. Any hints? (Why not do this by simply take x[1:6]? I have several
vectors a couple of thousand observations long with varying numbers of
NA's in the end. I'd prefer not to search through all of these one at a
time.)

Robert