Liviu, Thanks for your attention and help!
Sorry for attached csv file, I didn't read R-Help Posting guide careful. Another R-helper thaught me use de dput() function, and this output are in email's end. Your correction in my code works pretty well!! Now I can understand a little more how the R "think"! Thanks a lot! Also thanks for the suggetion to use sessionInfo(). I will do that on next questions to list. All best, and thanks very much again, Raoni The dput() of data is: structure(list(Data = structure(c(1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 2L, 2L, 2L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 4L, 4L, 4L, 4L, 4L, 5L, 5L, 5L), .Label = c("2011-02-04", "2011-02-05", "2011-02-07", "2011-02-08", "2011-02-09", "2011-02-10", "2011-02-11", "2011-02-14", "2011-02-15", "2011-02-16", "2011-02-17", "2011-02-18", "2011-02-21", "2011-02-22", "2011-02-23", "2011-02-24", "2011-02-25", "2011-02-28", "2011-03-01", "2011-03-02", "2011-03-03", "2011-03-04", "2011-03-10", "2011-03-11", "2011-03-14", "2011-03-15", "2011-03-16", "2011-03-17", "2011-03-28", "2011-03-29", "2011-03-30", "2011-03-31", "2011-04-01", "2011-04-04", "2011-04-05", "2011-04-06", "2011-04-07" ), class = "factor"), Fisherman = structure(c(5L, 1L, 2L, 5L, 1L, 2L, 1L, 2L, 5L, 5L, 2L, 1L, 2L, 5L, 1L, 2L, 5L, 1L, 5L, 5L, 2L, 1L, 5L, 1L, 2L, 5L, 1L, 2L, 5L, 1L), .Label = c("Yellow", "Blue", "White", "Green", "Red"), class = "factor"), N = c(0L, 1L, 1L, 0L, 0L, 0L, 0L, 0L, 1L, 1L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 1L, 1L, 0L, 0L, 1L, 0L, 0L, 0L, 0L, 0L, 0L, 0L)), .Names = c("Date", "Fisherman", "N"), row.names = c(NA, 30L), class = "data.frame") 2011/4/9 Liviu Andronic <landronim...@gmail.com>: > Hello > > On Fri, Apr 8, 2011 at 12:38 AM, Raoni Rodrigues > <caciquesamu...@gmail.com> wrote: >> Hello all! >> >> I have a data frame with nine variables and 293 cases. (attached goes >> the csv file). >> > The CSV didn't get through so it's difficult to replicate your > example. Please post the output of: > str(cpue) > > >> I need to calculate a index using the sum of one variable (N) divided >> by the length of other variable (Fisherman), but for each day (Date). >> >> I tried to use that codes: >> >> by (cpue, cpue$Date, function (x) sum (cpue$N)/length(cpue$Fisherman)) >> > [..] > >> In both codes, as result, I received the same value for all Date >> value. And, oddly, this result is the value of calculation for all >> data frame, as I used just: >> >> sum (cpue$N)/length(cpue$Fishermans) >> > From the code above, this is expected since in the function() > statement you use the entire df (cpue) and not the subset (x). Try > this: > by (cpue, cpue$Date, function (x) sum (x$N)/length(x$Fisherman)) > > >> Sorry for the basic question, but I worked on this simple code all day >> and can't do it work out! And have no idea why... >> >> I'm using R 2.11 in Windows XP. >> > It is often a good a idea to post the output of > sessionInfo() > > Regards > Liviu > > > >> Since now, thanks for the attention and all help, >> >> Best, >> >> Raoni >> >> ______________________________________________ >> 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. >> >> > > > > -- > Do you know how to read? > http://www.alienetworks.com/srtest.cfm > http://goodies.xfce.org/projects/applications/xfce4-dict#speed-reader > Do you know how to write? > http://garbl.home.comcast.net/~garbl/stylemanual/e.htm#e-mail > ______________________________________________ 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.