I just realized my earlier post of my question below was not in "Plain" Text mode, hence the repeat post...apologies! Kavitha
On Thu, Oct 22, 2009 at 4:19 PM, Kavitha Venkatesan <kavitha.venkate...@gmail.com> wrote: > Hi all, > > I would like to invoke a function that takes multiple arguments (some of > which are specified columns in the data frame, and others that are > independent of the data frame) on split parts of a data frame, how do I do > this? > > For example, let's say I have a data frame >>fitness_data > name height weight country > rob 5.8 200 usa > nancy 5.5 140 germany > jen 5.6 150 usa > clark 5.10 210 germany > matt 5.9 280 canada > ralph 6 270 canada > ... > ... > > Now let us say I have a function, my_func(h, w, noise, dir), which takes as > input: > (1) a vector of heights > (2) a vector of weights > (3) a user-input numeric "noise" value > (4) a user-input string "dir" for the directory to output the end result of > the function to > > This function does some calculations on the input data and outputs a > dataframe that is then written to a file in the "dir" directory. > > If I want to apply this function to data grouped by each country in the > "fitness_data" dataframe, how would I do this? I tried looking through the > mailing archives, but couldn't nail down the solution. I tried something > like > > split(mapply( function(a,b,c,d) my_func(fitness_data$h, fitness_data$w, 2.5, > my_directory)), fitness_data$country) > > but this considered fitness_data$h, and fitness_data$w in each single row > for a country, rather than a vector of heights or weights across all rows > corresponding to that country. > > Thanks! > > ______________________________________________ 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.
