R has no "cells". You need to do your homework by reading "An Introduction to R" , which ships with R, or one of the many R web tutorials of your choice. What you describe is trivial once you have made a minimal effort to learn R. In particular, ?"[" explains how to index data frames; but a tutorial is a better option for a learner.
-- Bert Bert Gunter Genentech Nonclinical Biostatistics (650) 467-7374 "Data is not information. Information is not knowledge. And knowledge is certainly not wisdom." H. Gilbert Welch On Sun, Apr 20, 2014 at 2:52 AM, Andre Zacharia <andre.zacha...@gmail.com> wrote: > Dear all, > > I am getting data columnwise that I need to divide by the mean of another > column > > If the column is the previous one this code works perfectly well: > > fun1 <- function(beginColumn, by, data) { indx <- seq(beginColumn, > ncol(data), by = by) as.data.frame(t(100 - (t(data[, indx])/colMeans(data[, > indx - 1], na.rm = TRUE)) * 100)) > } > (Arun helped me with this code, thank you again!...) > > But, the things is now more complicated... > > I need to program a function that allow me to divide for example cells from > column 3 on mean from column 2 and cells from column 4 on mean of column 2 > and the 5 etc. Then column 6 is another column from whch I need to extract > the mean and to do the same with column 7 and 8, etc... > > so if I have: > > 1 2 3 4 1 5 > 2 5 4 7 2 8 > 3 4 5 9 3 7 > 4 7 7 9 4 3 > > The serie 1,2,3,4 ar just enumerating so not useful at this timepoint. > > the results should be (from excel...): > 4,5 33,3333333 11,1111111 -11,1111111 11,1111111 -55,5555556 -77,7777778 > -11,1111111 -100 -55,5555556 -55,5555556 -100 > 33,3333333 > I tried to work on modyfying indx-1 by 2*indx-2, but this is not doing the > job... I tried many other things so that I am now stucked. > > Does Anyone has a brilliant idea? > > Many many thanks > > André ZACHARIA > > [[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. > ______________________________________________ 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.