Thank you very much, both Dimitris and Erik. Erik - you are right, I was trying to remove any duplication (i.e., if there are the same values in 2 or 3 or 4 columns). And it looks like that's what your solution does. But doesn't it do the same thing as Dimitris' solution?
Dimitri On Mon, Sep 21, 2009 at 2:55 PM, Erik Iverson <eiver...@nmdp.org> wrote: > Hello, > > Do you mean exactly any 2 columns. What if the value is equal in more than 2 > columns? > >> >> I built a data frame "grid" (below) with 4 columns. I want to exclude >> all rows that have equal values in ANY 2 columns. Here is how I am >> doing it: >> >> index<-expand.grid(1:4,1:4,1:4,1:4) > > If a value is equal in 2 or more rows, i.e., duplicated, then the following > should work, assuming index can be changed to a matrix for apply ... > > t3 <- index[apply(index, 1, function(x) all(!duplicated(x))),] > -- Dimitri Liakhovitski Ninah.com dimitri.liakhovit...@ninah.com ______________________________________________ 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.
