Re: How to test for "integer"?

[Robert A. Macy]

Thought I just didn't see the test.  


I've already checked the variable to see if it is complex.

I like your idea...

if (mod(abs(n),1)==0)
  message="n is an integer"
endif
  
is my 2nd test, but...

if (floor(x)==abs(x))
  message="x is a positive real integer"
endif

...does all 3 tests in a single line, thanks.



What is the advantage of using a built-in function?
Does a built-in function make it faster?

         - Robert -


On Sun, 15 May 2005 13:39:03 -0700
 Keith Goodman <address@hidden> wrote:
> I don't know of a built-in isint function.
> 
> But you can make your own. I'd use floor(x)==x since
> floor is a
> built-in function but mod isn't. Plus it won't crash on
> complex
> numbers. Either way I don't think you need abs.
> 
> On 5/15/05, Robert A. Macy <address@hidden> wrote:
> > Group,
> > 
> > Is there a direct test for integer?
> > 
> > I've been using
> > 
> > if (abs(mod(n,1))==0)
> >   msg="n is an integer"
> > endif
> > 
> > which works great.
> > 
> > I looked through the octave manual and didn't recognize
> an
> > "integer" test.
> > 
> >                - Robert -
> > 



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