On 10/5/07, Leeds, Mark (IED) <Mark.Leeds at morganstanley.com> wrote: > x[is.na(x)]<- y[is.na(x)] but this will only work correctly if x and y > are the same length so I hope that is > what you mean by the same style. That can be fixed if y is at least as long as to reach the last NA in x like this: x[is.na(x)] <- y[which(is.na(x))]