Hello, I had to give some more information to my posting:
as ouput there are more than one row, depending on the values of column A (transformierung to distinct values, here 3 and 4, but there are much more) > A B C > 1 3 6 5 > 2 3 4 20 > 3 3 8 2 > 4 4 8 3 > 5 4 2 6 Output: > A B C num rows > 1 3 6 6.16 3 > 2 4 5 4.00 3 B is mean and C variance. thank you Macki > Hello, > > it seems to be a simple problem, but I couldn't find an answer in the > archiv. (I think, it must has something to do with the group-select, like > in > php) > > I've the following data.frame: > > A B C > 1 3 6 5 > 2 4 4 20 > 3 5 8 2 > > I want to get the number of the rows in the 4th column, like: > > A B C num rows > 1 3 6 6.16 3 > > > (B is mean, C is variance by using summaryBy(B+C~ A, data=daten, > FUN=c(mean,var)) from the doBy-package) > > But, how can I add the column 'numrow' and count the number of the rows? > > Thanks! > > Macki > > ______________________________________________ > [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. > ______________________________________________ [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.
