[Rd] hashing NaN (PR#1267)

[tlumley@u.washington.edu]

Different NaNs can hash to different values and so be treated differently
by duplicated(), unique(), match(). Any IEEE double value with exponent
bits all 1 is NaN (except the one that is NA).

AFAICT all arithmetic and mathematical operations in R produce the same
NaN, but this is not guaranteed by any standard. read.spss() will produce
different NaNs when reading missing values in at least some circumstances.


	-thomas

Thomas Lumley			Asst. Professor, Biostatistics
tlumley@u.washington.edu	University of Washington, Seattle


-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-
r-devel mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html
Send "info", "help", or "[un]subscribe"
(in the "body", not the subject !)  To: r-devel-request@stat.math.ethz.ch
_._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._