[R] lag a data.frame column?

[Mark Knecht]

Sometimes it's the simple things...

Why doesn't this lag X$x by 3 and place it in X$x1? (i.e. - Na's in
the first 3 rows and then values showing up...)

The help page does talk about time series. If lag doesn't work on
data.frame columns then what would be the right function to use to lag
by a variable amount?

Thanks,
Mark


X=data.frame(x=seq(1:10))
X$x1=lag(X$x, 3)
X