See ?ave and try this: a[as.numeric(ave(a[,1], a[,1], FUN = length)) > 1, ]
On Sun, Aug 31, 2008 at 2:19 AM, Yuan Jian <[EMAIL PROTECTED]> wrote: > Hi, > > I have a matrix. >>a<-cbind(c("a","b","a"),c(4,3,6)) > [,1] [,2] > [1,] "a" "4" > [2,] "b" "3" > [3,] "a" "6" > > I want to remove rows in matrix a whose first column has frequency less than > 2. > in about example matrix a becomes > [,1] [,2] > [1,] "a" "4" > [2,] "a" "6" > > > > > > [[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.