Start out with merge(): > df <- merge(df1, df2, all.x=TRUE) # could add by="location" for emphasis > df location Name Position Country 1 36 cristina B <NA> 2 75 francesca A UK You could make make your 'Match' column from is.na(df$Country) if you knew that df2$Country were never NA. Otherwise you can add a fake variable to the merge to tell which output rows come from unmatched rows in the first data.frame:
> df12 <- merge(df1, cbind(df2, fromDF2=TRUE), all.x=TRUE, by="location") > df12$Match <- !is.na(df12$fromDF2) > df12 location Name Position Country fromDF2 Match 1 36 cristina B <NA> NA FALSE 2 75 francesca A UK TRUE TRUE Bill Dunlap Spotfire, TIBCO Software wdunlap tibco.com > -----Original Message----- > From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On > Behalf Of francy > Sent: Monday, October 03, 2011 10:55 AM > To: r-help@r-project.org > Subject: [R] Merge two data frames and find common values and non-matching > values > > Hi, > > I am trying to find a function to match two data frames of different lengths > for one field only. > So, for example, > df1 is: > > Name Position location > francesca A 75 > cristina B 36 > > And df2 is: > > location Country > 75 UK > 56 Austria > > And I would like to match on "Location" and the output to be something like: > > Name Position Location Match > francesca A 75 1 > cristina B 36 0 > > I have tried with the function 'match' or with: > subset(df1, location %in% df2) > But it does not work. > > Could you please help me figure out how to do this? > > Thank you! > -f > > > -- > View this message in context: > http://r.789695.n4.nabble.com/Merge-two-data-frames-and-find-common- > values-and-non-matching-values-tp3868299p3868299.html > Sent from the R help mailing list archive at Nabble.com. > [[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. ______________________________________________ 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.