Hi, As an example, how can I get the data such that field a of ab, ab["a"], equals 3? I expect the answer to be the union of 2 and 4, as
Thanks, > a<-c(1,3,4,3,5,6,5) > b<-c(2,4,6,7,3,1,2) > ab<-data.frame(a,b) > ab a b 1 1 2 2 3 4 3 4 6 4 3 7 5 5 3 6 6 1 7 5 2 > ab[a==3] Error in `[.data.frame`(ab, a == 3) : undefined columns selected > ab[ab["a"]==3] [1] 3 3 4 7 [[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.