Hallo On 30 May 2005 at 9:15, zhihua li wrote:
> hi netters > > I have a rather simple question. I have a data frame with two Well, I do not understand you simple question fully. You have something like that dat<-data.frame(X=1:100, Y=sample(1:10,10)) dat$X<-factor(dat$X) dat$Y<-factor(dat$Y) dat$Y[5]<-10 > variables X and Y, both of which are factors. X has 100 levels while Y > has 10 levels only. The data frame has 100 rows in all, so for X the > values are unique, and Y has many replicate values. Now I wanna > reduce the data frame into 10 rows only, according to the 10 levels of > Y. I don't care which value of X is in the same row with Y in the > final data frame, as long as it is in agreement with the original data > frame. Do you want to choose only some rows from your data frame to get unique Y and any corresponding X? dat[!duplicated(dat$Y),] Or do you want something different? HTH Petr > > I think this task can be carried out with some function like > aggregate. but I failed in figuring it out. Could anybody give me a > hint? > > Thanks a lot! > > ______________________________________________ > R-help@stat.math.ethz.ch mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide! > http://www.R-project.org/posting-guide.html Petr Pikal [EMAIL PROTECTED] ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html