[R] how to get unique vectors

Prof Brian Ripley ripley at stats.ox.ac.uk
Wed Dec 19 23:17:49 CET 2001

On Wed, 19 Dec 2001, Jason Liao wrote:

> First, happy holidays, everyone! Thanks to the R team for bringing out
> 1.4 before the new year.
> I have 10000 integer triplets stored in A[1:10000, 1:3]. I would like
> to find the unique triplets among the 10000 ones with possible
> duplications. What is the easiest way for this. I know the function
> unique(), which apply to a vector, not the 10000*3 array in my problem.

Well, new in 1.4.0 is unique.data.frame(), so you could either use that or
copy its idea.

Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272860 (secr)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

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