There was a post from Martin Maechler some years ago and I had to search a bit to find it. For these sorts of issues, I typically trust his judgement.
The post is here: https://stat.ethz.ch/pipermail/r-help/2003-April/032471.html His solution also handles complex numbers. HTH, Marc Schwartz On Sep 8, 2011, at 1:37 PM, Bert Gunter wrote: > Have a close look at ?storage.mode and ?typeof. > > The problem here, as usual and as you seem to allude is: define > "integer" . Mathematically, there is an unequivocal definition, but > not so in finite precision arithmetic. Are you referring to the > machine representation (typeof()), or the approximate value. And if > the latter, how approximate? > > I think both your solution and its perceived "beauty" will depend on > your exact definition and context. > > You may receive wiser advice. If so, please ignore mine. > > Cheers, > > Bert > > On Thu, Sep 8, 2011 at 11:27 AM, Alexander Engelhardt > <[email protected]> wrote: >> Hi, >> >> x <- 0.2*5 >> is.integer(x) >> >> gives me FALSE because R stores it as a float number, right? >> Is there an elegant way to work around that problem? Right now >> I'm using >> >> x <- 0.2*5 >> round(x) == x >> >> which returns TRUE. But more strictly I should use all.equal(), >> right? >> >> I somehow just don't like the--pardon--ugliness of those pieces >> of code. Maybe there is a beautiful way to write that. If not, >> no big problem -- I just like beautiful code :-) >> >> Cheers, >> Alex >> >> ______________________________________________ >> [email protected] 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. >> > > > > -- > "Men by nature long to get on to the ultimate truths, and will often > be impatient with elementary studies or fight shy of them. If it were > possible to reach the ultimate truths without the elementary studies > usually prefixed to them, these would not be preparatory studies but > superfluous diversions." > > -- Maimonides (1135-1204) > > Bert Gunter > Genentech Nonclinical Biostatistics > 467-7374 > http://pharmadevelopment.roche.com/index/pdb/pdb-functional-groups/pdb-biostatistics/pdb-ncb-home.htm > > ______________________________________________ > [email protected] 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. ______________________________________________ [email protected] 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.
