When you combine zoo objects with arithmetic it merges them using all = FALSE:
> library(zoo) > x <- data.frame(a=1:5*2, b=1:5*3) > x <- zoo(x); x a b 1 2 3 2 4 6 3 6 9 4 8 12 5 10 15 > > # these two are the same > > x$a/x$a[1] 1 1 > > m <- merge(x$a, x$a[1], all = FALSE) > m x$a x$a[1] 1 2 2 > m[,1]/m[,2] 1 1 On Sun, May 16, 2010 at 3:00 AM, Sean Carmody <seancarm...@gmail.com> wrote: > I am a bit confused about the different approaches taken to recycling in > plain data frames and zoo objects. When carrying out simple arithmetic, > dataframe seem to recycle single arguments, zoo objects do not. Here is an > example > >> x <- data.frame(a=1:5*2, b=1:5*3) >> x > a b > 1 2 3 > 2 4 6 > 3 6 9 > 4 8 12 > 5 10 15 >> x$a/x$a[1] > [1] 1 2 3 4 5 >> x <- zoo(x) >> x$a/x$a[1] > 1 > 1 >> > > I feel understanding this difference would lead me to a greater > understanding of the zoo module! > > Sean. > > -- > Sean Carmody > Twitter: http://twitter.com/seancarmody > Stable: http://mulestable.net/sean > > The Stubborn Mule > Blog: http://www.stubbornmule.net > Forum: http://mulestable.net/ > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. > ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.