On Fri, Apr 15, 2011 at 6:10 PM, zhenjiang xu <zhenjiang...@gmail.com> wrote: > Thanks, Dennis! I'll go with it. It's surprising there is no ready way to do > that. I imagine it should be a common data manipulation to add two > data.frame from two different sources. It could happen that one data.frame > is missing some rows while the other have some more. >
If you represent them as zoo series then you can do it using + (although the definition of + is different than in your post). Here "a", "b" and "c" are the "times": library(zoo) a <- zoo(1:3, letters[1:3]) b <- zoo(c(6, 1), c("a", "c")) a+b The last line gives: > a+b a c 7 4 To use the definition in your post one could do this (which has the effect of modifying b so that a+b works as in your post): merge(a, b, fill = 0, retclass = NULL) a+b The last line gives: > a+b a b c 7 2 4 -- Statistics & Software Consulting GKX Group, GKX Associates Inc. tel: 1-877-GKX-GROUP email: ggrothendieck at gmail.com ______________________________________________ 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.