When you subset, the factors will carry along all the original levels. You can remove them in your processing by:
x$fac <- factor(x$fac) > x <- data.frame(fam=c('a','a','b'), grp=c('1','2','3')) > # split > x.s <- split(x, x$fam) > # notice additional levels > str(x.s$b) 'data.frame': 1 obs. of 2 variables: $ fam: Factor w/ 2 levels "a","b": 2 $ grp: Factor w/ 3 levels "1","2","3": 3 > > z <- x.s$b > str(z) 'data.frame': 1 obs. of 2 variables: $ fam: Factor w/ 2 levels "a","b": 2 $ grp: Factor w/ 3 levels "1","2","3": 3 > z$grp <- factor(z$grp) # remove extra levels > str(z) 'data.frame': 1 obs. of 2 variables: $ fam: Factor w/ 2 levels "a","b": 2 $ grp: Factor w/ 1 level "3": 1 > On Fri, May 27, 2011 at 12:20 PM, Jeanna <stro...@uw.edu> wrote: > I may have prematurely excited... > > I ended up using the split method since my family indicators are > alphanumeric so my issue is as follows. > > I'm applying this to different subsets of my main data set. The subsets do > not contain all families. When I run the method on one of my subsets I get > back a table that includes ALL the families. Those that weren't in the > subset to which I applied the method have <NA> for all of the fields. > > If I export one of the subsets, restart R (to be certain nothing of my > original playtime is left) and import only the subset, the method works > perfectly. > > The addition of the previously removed rows seems to happen at the 'split' > step. > > Is there something I'm doing incorrectly? I can't seem to figure out how to > convince R not to look at my original data frame when deciding how many > families there are. > > -- > View this message in context: > http://r.789695.n4.nabble.com/Count-of-rows-while-looping-through-data-tp3547949p3555752.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 Data Munger Guru 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.