[R] how to judge a virable is a integer?

[PO SU]

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: desolator88 at 163.com 
Majored in Statistics from SJTU

At 2014-10-18 22:48:15, "Sergio Fonda" <sergio.fonda99 at 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 <rhelpmaillist at 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: desolator88 at 163.com

Majored in Statistics from SJTU







At 2014-10-18 20:10:09, "S Ellison" <S.Ellison at 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

>

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