On 11/3/06, Barry Rowlingson <[EMAIL PROTECTED]> wrote: > How do you know that step works? If the dataframe 'mental' doesnt have > an 'Rx' column then mental$Rx will be 'NULL', and the factor() function > will make a factor out of that...
Good point. I rarely use factors and missed that one. Happily, my inaccurate solution turned out to solve the problem anyway. Sarah -- Sarah Goslee http://www.functionaldiversity.org ______________________________________________ [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.
