Hi: Here's a *reproducible* example:
> a <- data.frame(w = rnorm(10), x = rnorm(10), y = rnorm(10), z = rnorm(10)) > b <- data.frame(w = rnorm(20), x = rnorm(20), x2 = rnorm(20), x3 = rnorm(20)) > commonCols <- intersect(names(a), names(b)) > commonCols [1] "w" "x" > rbind(a[commonCols], b[commonCols]) HTH, Dennis On Thu, Jul 29, 2010 at 3:53 AM, pdb <ph...@philbrierley.com> wrote: > > I have 2 data frames (A & B) with some common column names. > > A has 10 rows. > B has 20 rows. > > How do I combine them so I end up with a data frame with 30 rows that only > contains the common columns. > > I was trying 'merge' (Merge two data frames by common columns .....etc. ) > but that is not giving me what I expect... > > > a <- iris > > b <- iris > > > > c <-merge(a,b) > > > > NROW(a) > [1] 150 > > NROW(c) > [1] 152 > > Why is there only 152 rows and not 300? > > > > -- > View this message in context: > http://r.789695.n4.nabble.com/how-to-stack-data-frames-tp2306284p2306284.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. > [[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.
