A iterative and lagging function similar to diff in R, but not just difference?

Question

The diff function in R returns suitably lagged and iterated differences.

x = c(1, 2, 1, 3, 11, 7, 5)
diff(x)
# [1]  1 -1  2  8 -4 -2
diff(x, lag=2)
[1]  0  1 10          


        

Answer 1

You can use zoo::rollapply

require(zoo)
x <- c(1, 2, 1, 3, 11, 7, 5)
rollapply(x, width = 2, FUN = sum)
## [1]  3  3  4 14 18 12