Error saying Error in lag x 1 unused argument 1

Question

I need to refer to lagged and lead values of variables but I cannot seem to get the code for the lag function working as documented.

> library(dplyr)
> x <- seq(100,500,100)
> x
[1] 100 200 300 400 500
> lead(x,1)
[1] 200 300 400 500  NA
> lag(x,1)
Error in lag(x, 1) : unused argument (1)
> 

Answer 1

lag only works as expected with time-series objects. For instance:

cbind(x = ts(1:10), y = lag(1:10, -1))

In your case:

lag_n <- function(x, n) {c(rep(NA, n), x)[1:length(x)])