Hi Jan, You can do it in two ways. The simplest one is the following. The first option is to use $. Here is how: dogs <- data.frame(a = 1:10, b = 10:1) dogs$c <- dogs$a+dogs$b dogs
The second way it to use ?within ----------------Contact Details:------------------------------------------------------- Contact me: tal.gal...@gmail.com | 972-52-7275845 Read me: www.talgalili.com (Hebrew) | www.biostatistics.co.il (Hebrew) | www.r-statistics.com (English) ---------------------------------------------------------------------------------------------- On Thu, Jun 28, 2012 at 12:10 PM, Jan Näs <j...@plattfot.com> wrote: > Hi > > Newbie question: > > I have a set of data frames that I want to do the same calculations on > each. > I've found out that I can put them in a list and loop through the list > to do the calculation, but not put the results back into each > data.frame.. > > For example three data frames cats, dogs, birds > > where >cats > > name eats_kg > 1 bob 3 > 2 garfield 4 > 3 chuck 6 > > and dogs and birds are similar but not same length. > > On each data frame I now want to add a column with cost of food by > calculating "eats_kg"*price of food. > > So question is, can I put all data frames into one loop which returns > a new column for each? > > Ive tried > > MyList <- list(cast,dog,birds) > > for(i in 1:length(MyList)){ > price <- as.data.frame(myList[i])[,2] * cost > .. and then Im stuck. How can I put "price" back into each data frame? > > Thanks in advance. > > ______________________________________________ > 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.