Hi Rui, I thought the OP was looking for something like this: May be I am wrong. dat2<-dat1[order(dat1$Trip_id,dat1$Vessel,dat1$CommonName,dat1$Length,dat1$Count),] dat3<-dat2 dat3$Prop<-unlist(tapply(dat3$Count,list(dat3$Trip_id,dat3$CommonName),function(x) x/sum(x))) head(dat3) # Trip_id Vessel CommonName Length Count Prop #1 230 Sunlight Alewife 17 1 0.01408451 #2 230 Sunlight Alewife 18 1 0.01408451 #3 230 Sunlight Alewife 20 2 0.02816901 #4 230 Sunlight Alewife 21 4 0.05633803 #5 230 Sunlight Alewife 22 16 0.22535211 #6 230 Sunlight Alewife 23 22 0.30985915 A.K.
----- Original Message ----- From: Rui Barradas <ruipbarra...@sapo.pt> To: Sally_roman <sro...@umassd.edu> Cc: r-help@r-project.org Sent: Thursday, October 25, 2012 11:59 AM Subject: Re: [R] trying ti use a function in aggregate Hello, Try the following. (I've changed your function a bit. And named the data.frame 'dat', not 'data', which is an R function.) myfun <- function (x) ifelse(sum(x) == 0, 0, x/sum(x)) aggregate(Count ~ Trip_id + Length + CommonName, data = dat, myfun) The output shows that each and every group corresponds to a single row of the original df. The 1's represent 100%, myfun _is_ dividing by sum(Count) Trip_id/Length/CommonName group. If you want just Trip_id/CommonName, use aggregate(Count ~ Trip_id + CommonName, data = dat, myfun) Or use your instruction without 'Length' in the by list: b <- with(dat, aggregate(x=list(Percent=Count), by=list(Trip_id=Trip_id, Species=CommonName), FUN = myfun)) b Trip_id Species Percent 1 230 Alewife 0.01408451 2 230 Herring,Blueback 0.11111111 3 230 Shad,American 0.09090909 4 231 Shad,American 0.14285714 As you can see, the results are the same, with different output colnames. Hope this helps, Rui Barradas Em 25-10-2012 15:19, Sally_roman escreveu: > Hi -I am using R v 2.13.0. I am trying to use the aggregate function to > calculate the percent at length for each Trip_id and CommonName. Here is a > small subset of the data. > Trip_id Vessel CommonName Length Count > 1 230 Sunlight Shad,American 19 1 > 2 230 Sunlight Shad,American 20 1 > 3 230 Sunlight Shad,American 21 1 > 4 230 Sunlight Shad,American 23 1 > 5 230 Sunlight Shad,American 26 1 > 6 230 Sunlight Shad,American 27 1 > 7 230 Sunlight Shad,American 30 2 > 8 230 Sunlight Shad,American 33 1 > 9 230 Sunlight Shad,American 34 1 > 10 230 Sunlight Shad,American 37 1 > 11 230 Sunlight Herring,Blueback 20 1 > 12 230 Sunlight Herring,Blueback 21 2 > 13 230 Sunlight Herring,Blueback 22 5 > 14 230 Sunlight Herring,Blueback 26 1 > 15 230 Sunlight Alewife 17 1 > 16 230 Sunlight Alewife 18 1 > 17 230 Sunlight Alewife 20 2 > 18 230 Sunlight Alewife 21 4 > 19 230 Sunlight Alewife 22 16 > 20 230 Sunlight Alewife 23 22 > 21 230 Sunlight Alewife 24 16 > 22 230 Sunlight Alewife 25 4 > 23 230 Sunlight Alewife 26 1 > 24 230 Sunlight Alewife 27 2 > 25 230 Sunlight Alewife 28 2 > 26 231 Western Venture Shad,American 23 1 > 27 231 Western Venture Shad,American 24 1 > 28 231 Western Venture Shad,American 25 1 > 29 231 Western Venture Shad,American 28 2 > 30 231 Western Venture Shad,American 29 2 > > My code is: > myfun<-function (x) x/sum(x) > b<-with(data,aggregate(x=list(Percent=Count),by=list(Trip_id=Trip_id,Length=Length,Species=CommonName), > FUN="myfun")) > > My issue is that the percent is not be calculated by Trip_id and CommonName. > The result is that each row has a percent of 1 indicating that myfun is not > dividing by the sum of counts with a Trip_id/CommonName group. Any help > would be appreciated. > Thank you > > > > > > -- > View this message in context: > http://r.789695.n4.nabble.com/trying-ti-use-a-function-in-aggregate-tp4647414.html > Sent from the R help mailing list archive at Nabble.com. > > ______________________________________________ > 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. ______________________________________________ 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.
