Will most likely expose that I am new to R, but in SPSS, running lags is very easy. Obviously this is user error, but what I am missing?
x <- sample(c(1:9), 10, replace = T)
y <- lag(x, 1)
ds <- cbind(x, y)
ds
Results in:
x y
[1,] 4 4
[2,] 6 6
[3,] 3 3
[4,] 4 4
[5,] 3 3
[6,] 5 5
[7,] 8 8
[8,] 9 9
[9,] 3 3
[10,] 7 7
I figured I would see:
x y
[1,] 4
[2,] 6 4
[3,] 3 6
[4,] 4 3
[5,] 3 4
[6,] 5 3
[7,] 8 5
[8,] 9 8
[9,] 3 9
[10,] 7 3
Any guidance will be much appreciated.
Another way to deal with this is using the zoo package, which has a lag method that will pad the result with NA:
require(zoo)
> set.seed(123)
> x <- zoo(sample(c(1:9), 10, replace = T))
> y <- lag(x, -1, na.pad = TRUE)
> cbind(x, y)
x y
1 3 NA
2 8 3
3 4 8
4 8 4
5 9 8
6 1 9
7 5 1
8 9 5
9 5 9
10 5 5
The result is a multivariate zoo object (which is an enhanced matrix), but easily converted to a data.frame via
> data.frame(cbind(x, y))