Dear useRs,
I want to write a function that generates all the possible combinations of
diff().
Example:
If my vector has length 5, I need the diff() until lag=4 ->
c(diff(my.vec), diff(my.vec, lag=2), diff(my.vec, lag=3), diff(my.vec, lag=4))
If it has length 4, I need until lag=3 ->
c(diff(my.vec), diff(my.vec, lag=2), diff(my.vec, lag=3))
So, it must be until lag=(length(my.vec)-1).
The function I've written is:
dif <- function(my.vec) {
for(i in 2:(length(my.vec)-1)) {
x.dif <- c(diff(my.vec), diff(my.vec, lag=i))
}
return(x.dif)
}
But it only returns the first diff() (lag=1) and the last one ( diff(my.vec,
lag=(length(my.vec)-1) )
Example:
> my.vec = c(1,2,3,2)
> dif(my.vec)
[1] 1 1 -1 1
What I wanted to get was:
> c(diff(my.vec), diff(my.vec, lag=2), diff(my.vec, lag=3))
[1] 1 1 -1 2 0 1
Is there a way of computing it so R understands what I want?
Thanks in advance, happy new year for everyone!
Kind regards,
Rafael.
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