On Wed, Aug 15, 2012 at 10:37:17PM +1000, Tom Bird wrote: > Hi, > > I am using 32-bit R v 2.15.1, on Mac OsX v 10.6.8 with R GUI 1.52 Leopard > build 32-bit (6188). I have also replicated this error on R 2.13.2 on a > windows 7 machine. > > In some sequences of numbers, I am unable to use the which() function to > index certain values. It seems to be primarily numbers with a 3 in the > decimal. > For example: > > > S=seq(0,4,0.01) > > > which(S==2.02) > > [1] 203 > > > which(S==2.03) > > integer(0) > > > which(S==2.04) > > [1] 205 > > > which(S==2.04) > > [1] 205 > > > which(S==3.03) > > integer(0) > > > which(S==3.3) > > integer(0) > > > which(S==3.) > > [1] 301 > > > which(S==3.5) > > [1] 351
Hi. This is a rounding problem. print(S[204], digits=20) [1] 2.0300000000000002487 print(2.03, digits=20) [1] 2.0299999999999998046 Use function round(, digits), for example S <- round(seq(0,4,0.01), digits=7) which(S==2.03) [1] 204 which(S==3.03) [1] 304 Hope this helps. Petr Savicky. ______________________________________________ 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.
