Or if you need it to be fast, try data.table. X[Y] is a join when X and Y are both data.tables. X[Y] is a left join, Y[X] is a right join. 'nomatch' controls the inner/outer join i.e. what happens for unmatched rows. This is much faster than merge().
"Gabor Grothendieck" <ggrothendi...@gmail.com> wrote in message news:971536df0906100704q433f5f99ld3f9c23e69d95...@mail.gmail.com... Try: merge(completedf, partdf, all.x = TRUE) or library(sqldf) # see http://sqldf.googlecode.com sqldf("select * from completedf left join partdf using(beta, alpha)") On Wed, Jun 10, 2009 at 9:56 AM, Etienne B. Racine<etienn...@gmail.com> wrote: > > Hi, > > With two data sets, one complete and another one partial, I would like to > merge them and keep the unmatched lines. The problem is that merge() > dosen't > keep the unmatched lines. Is there another function that I could use to > merge the data frames. > > Example: > > completedf <- expand.grid(alpha=letters[1:3],beta=1:3) > partdf <- data.frame( > alpha= c('a','a','c'), > beta = c(1,3,2), > val = c(2,6,4)) > > mergedf <- merge(x=completedf, y=partdf, by=c('alpha','beta')) > # it only kept the common rows > nrow(mergedf) > > Thanks, > Etienne > -- > View this message in context: > http://www.nabble.com/Merge-data-frame-and-keep-unmatched-tp23962874p23962874.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. > ______________________________________________ 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.
