On Thu, Jul 24, 2008 at 10:39:34AM -0700, Nordlund, Dan (DSHS/RDA) wrote: [...] > Yes, it does help. I was misunderstanding how logical values are > used for indexing. I assumed incorrectly that a value would be > returned only if the index expression evaluated as TRUE. It would > seem that the philosophy is that not returning a value would imply > that the expression evaluated to FALSE. So, indexing with NA must > return something, and NA is the appropriate value to return since one > doesn't know what it is. > > Is that a reasonable summary?
Yes, I think so. (But I have to say that I'm not completely aware of the ideology behind this choice.) Gabor > Dan > > Daniel J. Nordlund > Washington State Department of Social and Health Services > Planning, Performance, and Accountability > Research and Data Analysis Division > Olympia, WA 98504-5204 > > > -- Csardi Gabor <[EMAIL PROTECTED]> UNIL DGM ______________________________________________ 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.
