1、
> a <- c(3,NA,NA,4,1,5) > b <- c(NA,4,6,2,4,9) > c <- data.frame(a,b) > c a b 1 3 NA 2 NA 4
3 NA 6
4 4 2
5 1 4
6 5 9
> c[is.na(c)] <- 0
> c a b 1 3 0
2 0 4
3 0 6
4 4 2
5 1 4
6 5 9
2、
> a <- c(3,NA,NA,4,1,5) > b <- c(NA,4,6,2,4,9) > c <- data.frame(a,b) > c a b 1 3 NA 2 NA 4
3 NA 6
4 4 2
5 1 4
6 5 9
> c[is.na(c)] <- "sss"
> c a b 1 3 sss 2 sss 4
3 sss 6
4 4 2
5 1 4
6 5 9