Dear list, I have a question about the selection of Variables in dataframes. I have a dataframes like this:
CFISCA FIRMS YEAR VAR VALUE 20345 nike 2005 EC01 34 20345 nike 2006 EC01 45 56779 mediaset 2005 EC01 65 64568 agazzini 2005 EC01 78 64568 agazzini 2006 EC01 56 78907 uniteam 2006 EC01 46 what my result should be is a new dataframes which have only firms which have data in both years (2005,2006) CFISCA FIRMS YEAR VAR VALUE 20345 nike 2005 EC01 34 20345 nike 2006 EC01 45 64568 agazzini 2005 EC01 78 64568 agazzini 2006 EC01 56 Thanks for your attention!!! ______________________________________________ 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.
