Dear Jens, Here is one way: x$sequ <- ave(x$dv, paste(x$block, x$trial, sep=""), FUN = function(x) seq(length(x)) ) x
where x is your data. HTH, Jorge On Fri, Jul 10, 2009 at 9:27 AM, Jens Bölte <[email protected]>wrote: > Hello, > > I have a data frame of the following form > > block trial dv > 1 1 10 > 1 1 11 > 1 1 9 > 1 2 12 > 1 2 9 > 1 3 12 > 1 3 13 > 1 3 14 > 1 3 15 > 1 4 12 > 1 4 11 > 1 4 10 > 1 4 9 > 1 4 11 > > and need to number the rows consecutively in the following manner > > block trial dv sequ > 1 1 10 1 > 1 1 11 2 > 1 1 9 3 > 1 2 12 1 > 1 2 9 2 > 1 3 12 1 > 1 3 13 2 > 1 3 14 3 > 1 3 15 4 > 1 4 12 1 > 1 4 11 2 > 1 4 10 3 > 1 4 9 4 > 1 4 11 5 > > Any idea how to solve this problem? I tried but did not succeed :-( > > Best Jens Bölte > > ______________________________________________ > [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. > > [[alternative HTML version deleted]]
______________________________________________ [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.

