3. all.equal(a, as.integer(a)) Note that this one tests if 'a' can be stored accurately as a 32-bit signed integer. If you want to know if 'a' can be used as an accurate count, then you want to test if a+1>a (use abs() in case a is negative). E.g., try this for a<-2^49-1, about 5*10^14.
You have to decide what properties of integers you are interested in. Bill Dunlap TIBCO Software wdunlap tibco.com On Sat, Oct 18, 2014 at 10:02 AM, PO SU <rhelpmaill...@163.com> wrote: > > Tks for your help, after investigate in your link, i find there seems three > ways can be adoped: > 1. is.wholenumber <- function(x, tol = .Machine$double.eps^0.5) abs(x - > round(x)) < tol) > e.g. is.wholenumber(1) > 2. x%%1==0 > > > 3. all.equal(a, as.integer(a)) > > > and also included your last suggestion using floor. and also tks for other > helpers! > > > > > > > > > -- > > PO SU > mail: desolato...@163.com > Majored in Statistics from SJTU > > At 2014-10-18 22:48:15, "Sergio Fonda" <sergio.fond...@gmail.com> wrote: > > > > Sorry for my previous hurry misunderstanding. > Try this link: > http://stackoverflow.com/questions/3476782/how-to-check-if-the-number-is-integer > > > > > 2014-10-18 16:25 GMT+02:00 PO SU <rhelpmaill...@163.com>: > > > > It's due to that, 1 is a numeric, 1.2 is a numeric, though it's true. but > deeply, when i want to know 1 is an integer, there seems no easy way to get > the answer. > > So, is there anyone happen to know it? > > > > > > > > > > -- > > > > PO SU > > mail: desolato...@163.com > > Majored in Statistics from SJTU > > > > > > > > At 2014-10-18 20:10:09, "S Ellison" <s.elli...@lgcgroup.com> wrote: > >>> But i use a<-10/b , b is some value ,may be 5, maybe 5.5 > >>If you do floating point arithmetic on integers you'll usually get floating >>point answers, including the 5.0. > >> > >>See FAQ 7.31 for the usual floating point problem, and ?all.equal for the >>usual answer to it. You could see if a result is close to an integer by,for >>example, using all.equal to compare it to itself after rounding. > >> > >>S > >> > >>******************************************************************* > >>This email and any attachments are confidential. Any use, copying or > >>disclosure other than by the intended recipient is unauthorised. If > >>you have received this message in error, please notify the sender > >>immediately via +44(0)20 8943 7000 or notify postmas...@lgcgroup.com > >>and delete this message and any copies from your computer and network. > >>LGC Limited. Registered in England 2991879. > >>Registered office: Queens Road, Teddington, Middlesex, TW11 0LY, UK > > ______________________________________________ > > 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. ______________________________________________ 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.