Dear Mark, Try this: lapply(yourlistofdataframes, function(d){ k <- ncol(d) d$product <- d[,k-1] * d[,k] d } )
HTH, Jorge On Thu, Jul 23, 2009 at 2:05 PM, Mark Na <mtb...@gmail.com> wrote: > Hi R-helpers, > > I have a list containing 10 elements, each of which is a dataframe. I wish > to add a new column to each list element (dataframe) containing the product > of the last two columns of each dataframe. > > I'd appreciate any pointers, thanks! > > Mark Na > > [[alternative HTML version deleted]] > > ______________________________________________ > 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. > [[alternative HTML version deleted]] ______________________________________________ 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.