[R] A question about is.interger function

[Dieter Menne]

Leon <amstat2006 <at> gmail.com> writes:

> 
> Hi, All
> I am using is.integer function to examine whether an object is an integer or 
not, but I get such results,
> 
> > x<-3
> > is.integer(x)
> [1] FALSE

x <- 3
typeof(3)
[1] "double"

This may not be a wise decision in hindsight, but probably was made to avoid 
conversion when in the next step you do

x[2] = 1.5

y <- as.integer(3)
 typeof(y)
[1] "integer"
 
> > x<-3:4
> > x
> [1] 3 4
> > is.integer(x)
> [1] TRUE

Here R seems to know that 3 is an integer, which I believe is a bit 
inconsistent, but wise, because mostly you use integers here. Mostly; because 

1.5:3.5 

gives a reasonable result

[1] 1.5 2.5 3.5

Dieter