On Tue, Sep 18, 2012 at 12:17 PM, Marta Miguel <martamigue...@gmail.com> wrote: > Dear all, > > > I have two different data frames, that have two common variables: date and > sample. Here is a small extract of both of them > >> head(traffic) > datet sessiont samplet buddleiat > 1 07-08-2012 1 1 1 > 2 07-08-2012 1 1 1 > 3 07-08-2012 1 1 1 > 4 07-08-2012 1 2 3 > 5 07-08-2012 1 2 1 > 6 07-08-2012 1 2 2 > 7 07-08-2012 2 3 4 > 8 07-08-2012 2 3 5 > 9 07-08-2012 2 3 5 > 10 07-08-2012 2 4 8 > 11 07-08-2012 2 4 4 > 12 07-08-2012 2 4 6 > 13 08-08-2012 1 1 9 > 14 08-08-2012 1 1 12 > 15 08-08-2012 1 1 7 > (...) > >> head(encounters) > datec samplec Bladen > 1 07-08-2012 1 9 > 2 07-08-2012 1 6 > 3 07-08-2012 1 8 > 4 07-08-2012 1 8 > 5 07-08-2012 1 5 > 6 07-08-2012 1 4 > 7 07-08-2012 1 7 > 8 07-08-2012 1 6 > 9 07-08-2012 1 4 > 10 07-08-2012 1 2 > 11 07-08-2012 1 7 > 12 07-08-2012 1 8 > (...) > > They don't have the same length. > > Using the function tapply, I managed to calculate the mean of the column > buddleiat (from traffic) by sample and date. > > tapply(buddleiat, list(samplet,datet), mean) > > > Now I want to divide each different value of Bladen by the value that has > the same number of sample and date of the buddleiat mean calculated. Being > that, different values from Bladen can be divided by the same value of > buddleiat mean. > > > I tried using this code: > >> budt=(Bladen/tapply(buddleiat, list(samplet,datet), mean)) > Error: dims [product 68] do not match the length of object [1360] > > But they don't have the same length, and I am not sure that it will do what > I am asking. > > > Do you have any suggestions? Is there a function I could use or will it be > easier to do it "manually" by creating a third data frame with both > variables and repeated values of the buddleiat means? > >
I believe changing tapply() --> ave() will be a good start. Cheers, Michael > I hope I made myself understand. > > > Thanks in advance, > > Marta Miguel > > [[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.
