try this (presuming that you want to find the missing lines based on the 2nd column of the data frames):
a[!a$col2 %in% b$col2, ] I hope it helps. Best, Dimitris ---- Dimitris Rizopoulos Ph.D. Student Biostatistical Centre School of Public Health Catholic University of Leuven Address: Kapucijnenvoer 35, Leuven, Belgium Tel: +32/(0)16/336899 Fax: +32/(0)16/337015 Web: http://www.med.kuleuven.be/biostat/ http://www.student.kuleuven.be/~m0390867/dimitris.htm ----- Original Message ----- From: "Vittorio" <[EMAIL PROTECTED]> To: <r-help@stat.math.ethz.ch> Sent: Friday, October 07, 2005 10:02 AM Subject: [R] finding missing lines... > Take this as an example: > >> a=data.frame(col1=c(1,2,3,4,5), col2=c > ("my","beloved","daughter","son","wife")) >> b=data.frame(col1=c(1,2,4), > col2=c("my","beloved","son")) >> a > col1 col2 > 1 1 my > 2 > 2 beloved > 3 3 daughter > 4 4 son > 5 5 wife >> b > > col1 col2 > 1 1 my > 2 2 beloved > 3 4 son > > As you can > see in b is equal to a with exception of lines of a with col1= 3 and > col1=5 that are missing. > > How can I obtain a third dataframe made of > the missing lines only, e.g. > >> c > col1 col2 > 1 3 daughter > 2 > 5 wife > > Ciao > Vittorio > > ______________________________________________ > R-help@stat.math.ethz.ch mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide! > http://www.R-project.org/posting-guide.html > Disclaimer: http://www.kuleuven.be/cwis/email_disclaimer.htm ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html