If I want to do a join based on *two* matching fields in two data frames, can merge() handle this? It appears to only handle a single matching column -- do I need to make a "metacolumn" or is there some way to do this? E.g.:
Dataframe 1 contains columns A,B,C and Dataframe 2 contains A,B,D I want an output A,B,C,D which places C and D together if A and B match (otherwise, make two new rows, e.g. Ax,Bx,Cx,nodata and Ay,By,nodata,Dy) --j -- Jonathan A. Greenberg, PhD NRC Research Associate NASA Ames Research Center MS 242-4 Moffett Field, CA 94035-1000 Office: 650-604-5896 Cell: 415-794-5043 AIM: jgrn307 MSN: [EMAIL PROTECTED] ______________________________________________ [email protected] 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.
