在dplyr的滚动总和

 library(zoo)
 df %>%  group_by(id) %>%
       mutate(Sum_prev = rollapply(x, list(-(1:5)), sum, fill=NA, align = "right", partial=F))  

#you can use rollapply(x, list((1:5)), sum, fill=NA, align = "left", partial=F) 
#to sum the next 5 elements scaping the current one 


     x id Sum_prev
 1   3  1         NA
 2   8  1         NA
 3   5  1         NA
 4   9  1         NA
 5  10  1         NA
 6   1  1         35
 7   6  1         33
 8   9  1         31
 9   6  1         35
 10  5  1         32
 11 10  2         NA
 12  5  2         NA
 13  7  2         NA
 14  6  2         NA
 15  2  2         NA
 16  9  2         30
 17  3  2         29
 18  1  2         27
 19  4  2         21
 20 10  2         19