Probably you use the idea from unique.matrix, that is 1) form a string from each row and 2) call match() to see which strings match your pattern row.
On Sun, 14 Aug 2005, Todd Remund wrote: > I am looking for a fast way to count the number of rows in a matrix are > identical to a pattern vector. For example, if I am interested in counting > the number of row vectors in a matrix that are identical to (1,2,3) what > would I do? I have tried the identical statement in a loop but this is far > too slow. I have a very large matrix and need to avoid loops at all costs. -- Brian D. Ripley, [EMAIL PROTECTED] 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 272866 (PA) Oxford OX1 3TG, UK Fax: +44 1865 272595 ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
