Dear useRs,
I'm trying to write a loop to sum my data in the following way:
(the second - the first) + (the third - the second) + (the fourth - the third) + ...
for each column.

So, I wrote something like this:

  c <- list()
  for(i in 1:ncol(mydata)) {
  for(j in 2:nrow(mydata)) {
  c[[i]] <- sum(yc[j,i] - yc[(j-1),i])
  }}}

As for the columns it works pretty fine, but it only returns the last subtraction, however, I need the sum of all subtractions.

Any ideas?

Regards,
Rafael.


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