You don't need grep for this. Use the merge() function and make sure the arguments all.x and all.y are considered depending on whether this is a left or right merge.
> -----Original Message----- > From: r-help-boun...@r-project.org > [mailto:r-help-boun...@r-project.org] On Behalf Of vpas > Sent: Monday, December 22, 2008 11:03 AM > To: r-help@r-project.org > Subject: [R] Matching > > > I understand this is an easy question, and have been playing > around with grep and the match function, but was hoping for a > little incite: > > I have one .csv with the following data: > > names values > A 1 > B 2 > C 3 > D 4 > > > The second .csv is: > > names > A > C > > > I am hoping to match all of the rows that appear in the > second .csv, making a new file that would look like this: > > names values > A 1 > C 3 > > > Here is what I have so far: > > my.data <- read.csv("rows.csv",sep=",") > my.selection <- read.csv("select.csv",sep=",") matched <- > match(my.data[,1], my.selection[,1]) my.data <- > my.data[matched] write.table(as.matrix(my.data), "select_RESULTS.txt") > > Unfortunately, this is throwing errors in row numbers... > > -- > View this message in context: > http://www.nabble.com/Matching-tp21130173p21130173.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.