Hi [EMAIL PROTECTED] napsal dne 20.11.2007 17:07:42:
> On 11/20/2007 10:50 AM, Ken Fullish wrote: > > > as.character(seq(-.25,.95,.1)) > > [1] "-0.25" "-0.15" "-0.05" "0.05" "0.15" "0.25" "0.35" "0.45" > > "0.55" "0.65" "0.75" "0.85" "0.95" > > > > > as.character(seq(-.35,.95,.1)) > > [1] "-0.35" "-0.25" > > "-0.15" "-0.0499999999999999" "0.05" > > [6] "0.15" "0.25" > > "0.35" "0.45" "0.55" > > [11] "0.65" "0.75" > > "0.85" "0.95" > > > > Not a big deal, just curiosity: > > Why do I obtain this "ugly" "-0.0499999999999999" instead of the > > expected "-0.05" ? > > Because as.character() tries to do an accurate conversion, and the > number in your vector is closer to -0.0499999999999999 than to -0.05. > You could get the "-0.05" by something like round( seq(...), 2). > > The reason seq() doesn't give you exactly -0.05 is that the starting > values and step size you've chosen are not exactly representable in R's > floating point format. It can only store fractions exactly when the > denominator is a power of 2. And it is not related exclusively to R but to floating point arithmetic in computer binary language. Regards Petr > > Duncan Murdoch > > ______________________________________________ > 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. ______________________________________________ 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.
