On Fri, Aug 20, 2010 at 2:19 PM, steven mosher <moshersteven at gmail.com>
wrote:> A quick question
>
> ?x <- as.yearmon(2000 + seq(0, 23)/12)
> ?x
> ?[1] "Jan 2000" "Feb 2000" "Mar 2000"
"Apr 2000" "May 2000" "Jun 2000" "Jul
> 2000" "Aug 2000" "Sep 2000" "Oct 2000"
"Nov 2000" "Dec 2000" "Jan 2001"
> [14] "Feb 2001" "Mar 2001" "Apr 2001"
"May 2001" "Jun 2001" "Jul 2001" "Aug
> 2001" "Sep 2001" "Oct 2001" "Nov 2001"
"Dec 2001"
> ?data<-seq(1,24,by=1)
> ?testzoo<-zoo(data,order.by=x)
>
> The operation I ant to perform on the zoo series is this. I will illustrate
> with a small example and formula:
>
> the coredata of the zoo series is ?1,2,3,4,5,6,7,8 ? ?)
> I want to calculate Result<- zoo[x]-zoo[x-1] ?(NA,1,1,1,1,1...NA)
> The first element of course is undefined(NA). is there any method to do
this
> elegantly, padding NAs at the
> start ?works but its ugly. if I get a simple function I can apply it to a
> matrix of zoo series
zoo has a diff.zoo method:
diff(testzoo)
diff(testzoo, na.pad = TRUE)