See: http://cran.r-project.org/doc/FAQ/R-FAQ.html#Why-doesn_0027t-R-think-these-numbers-are-equal_003f
On Wed, Sep 30, 2009 at 2:40 PM, Michael Knudsen <micknud...@gmail.com> wrote: > Hi, > > Today I was flabbergasted to see something that looks like a rounding > error in the very basic seq function in R. > >> a = seq(0.1,0.9,by=0.1) >> a > [1] 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 >> a[1] == 0.1 > [1] TRUE >> a[2] == 0.2 > [1] TRUE >> a[3] == 0.3 > [1] FALSE > > It turns out that the alternative > >> a = (1:9)/10 > > works just fine. Are there any good guides out there on how to deal > with issues like this? I am normally aware of rounding errors, but it > really surprised me to see that an elementary function like seq would > behave in this way. > > Thanks, > Michael Knudsen > > -- > Michael Knudsen > micknud...@gmail.com > http://sites.google.com/site/micknudsen/ > > ______________________________________________ > 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.