With the problem below, I've discoved that n95trt<-length(byyr$cnd95[byyr$cnd95=="tr"&!is.na(byyr$cnd95)]) does give me the correct count for the number of "tr" entries. (The same behavior occurs for the "c" level of the cnd95 factor.) It appears that byyr$cnd95=="tr" is finding both "tr" AND NA entries. Is this a bug, or is it to be expected?
Dave Subject: length() misbehaving? > I'm having a weird problem with length(), in R1.6.1 under windows2000. I have a > dataframe called byyr, with ten columns, the first of which is named cnd95. > summary(byyr) shows that byyr$cnd95 contains the factor level "tr" 66 times. Also, > when I enter byyr$cnd95 at the command line, I can count 66 "tr" elements in the > resulting vector. However, when I enter > > n95trt <- length(byyr$cnd95[byyr$cnd95=="tr"]) > n95trt > > the result is 68! Any ideas why this is happening, and how I can fix the miscount? > (That column also contains 69 entries of "c", and (relevantly?) two NA's.) > > Thanks for any help. > > Dave Parkhurst > > ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help
