here is some more info: http://r.789695.n4.nabble.com/file/n3932898/help.jpg this is what`s happend when I run the function in R I appreciate if someone can give me some inputs here Thanks in advance -- View this message in context: http://r.789695.n4.nabble.com/merging-two-dataframes-tp3932869p3932898.html Sent from the R help mailing list archive at Nabble.com.