Hi Boshao, Check ?duplicated.
HTH, Jorge On Thu, Oct 28, 2010 at 2:29 PM, boshao zhang <> wrote: > Dear everyone in the Mailing list: > > It is easy to get the unique elements in a column. But I would like to get > rid of those rows that the elements of this column are redundant. Or > sometimes, to have a look at the rows that the elements of this column are > redundant is also important. I guess it boils down to throw out the index of > the redundant elements. > > With millions of rows, how can I efficiently perform the task? > > Thank you in advance. > > Boshao > > > > [[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. > > [[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.
