This should do it for you: > x <- read.table('clipboard', header=TRUE) > x Id age mass 1 1 1 5.4 2 1 3 6.2 3 1 15 10.0 4 2 3 8.1 5 2 10 12.8 6 3 2 5.9 7 3 10 7.1 8 3 15 15.4 9 3 17 16.2 > x$NoCap <- ave(x$Id, x$Id, FUN=length) > x Id age mass NoCap 1 1 1 5.4 3 2 1 3 6.2 3 3 1 15 10.0 3 4 2 3 8.1 2 5 2 10 12.8 2 6 3 2 5.9 4 7 3 10 7.1 4 8 3 15 15.4 4 9 3 17 16.2 4 >
On Mon, Feb 9, 2009 at 7:36 AM, clion <birt...@hotmail.com> wrote: > > Hi there. > I collectad data of several animals (Id) that were caught and measured at > several occasions. > The dataframe looks like this: > Grouped Data: mass ~ age | Id > Id age mass > 1 1 5.4 > 1 3 6.2 > 1 15 10.0 > 2 3 8.1 > 2 10 12.8 > 3 2 5.9 > 3 10 7.1 > 3 15 15.4 > 3 17 16.2 > > Now, I would like to add a column that shows the number of captures per > Animal (so it'll look like this:) > Id .... NoCaps > 1 .... 3 > 1 .... 3 > 1 .... 3 > 2 .... 2 > 2 .... 2 > 3 .... 4 > 3 .... 4 > .... > > I understand that with > tapply(Id,Id, length) > I can find out how many times each animal was caught, but how do I get this > information into an extra column? I'm sure, this is an easy question, but > I'm lost, where to find the answer, or especially where to look it up. if > this is not a new question, please give me the key words to look for it... > > thanks in advance > > > > > > > -- > View this message in context: > http://www.nabble.com/length-of-object-in-repeated-measures-tp21911978p21911978.html > Sent from the R help mailing list archive at Nabble.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. > -- Jim Holtman Cincinnati, OH +1 513 646 9390 What is the problem that you are trying to solve? ______________________________________________ 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.