Try this: 1) Rows:
merge(as.data.frame(a), as.data.frame(b), sort = FALSE) 2) Index: merge(cbind(as.data.frame(a), Idx = 1:nrow(a)), as.data.frame(b), sort = FALSE)$Idx On Tue, Dec 9, 2008 at 12:57 PM, ppaarrkk <[EMAIL PROTECTED]> wrote: > > I want to compare two matrices or data frames and select or get an index > for > those rows which are the same in both. I have tried the following : > > > > > > > a = matrix ( 1:10, ncol = 2 ) > a > > b = matrix ( c ( 2,3,4,7,8,9 ), ncol = 2 ) > b > > a[a==b] > > > > > > > a = as.data.frame ( matrix ( 1:10, ncol = 2 ) ) > a > > b = as.data.frame ( matrix ( c ( 2,3,4,7,8,9 ), ncol = 2 ) ) > b > > a[a==b] > > > > > > > > > Any ideas please. > > > Thanks. > > > Simon Parker > Imperial College > > -- > View this message in context: > http://www.nabble.com/Selecting-rows-that-are-the-same-in-separate-data-frames-tp20916243p20916243.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. > -- Henrique Dallazuanna Curitiba-Paraná-Brasil 25° 25' 40" S 49° 16' 22" O [[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.
