> -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of > Williams, Michael > Sent: Monday, April 18, 2005 1:58 AM > To: r-help@stat.math.ethz.ch > Subject: [R] Minimum distance > > > G'day, I have a matrix 20000 x 500 populated with all the > distances between a list of airports and a list of towers. > What I'm having trouble doing is finding the closest airport > to each tower, Any help would be greatly appreciated.
Try: ( M <- matrix( rnorm( 24 ), 8, 3 ) ) rownames( M ) <- 1:8 ( wh <- sweep( M, 2, apply( M, 2, min ), "==" ) ) rownames(M)[ row( wh )[wh] ] It works in finite time even with M of 20000 by 500 but it breaks down if there is more than one minimum per column. Bendix Carstensen ---------------------- Bendix Carstensen Senior Statistician Steno Diabetes Center Niels Steensens Vej 2 DK-2820 Gentofte Denmark tel: +45 44 43 87 38 mob: +45 30 75 87 38 fax: +45 44 43 07 06 [EMAIL PROTECTED] www.biostat.ku.dk/~bxc ---------------------- > > Regards, > Michael Williams > > > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help@stat.math.ethz.ch mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read > the posting guide! http://www.R-project.org/posting-guide.html > ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html