Re: st: a question on function int

[Chris Kopp <kopp@soz.unibe.ch>]

Dear Zhang,

-help datatypes- explains that Stata saves numbers in binary format.  
Numbers less than 1, such as 0.005 in your case, may not have a  
perfect binary representation. So if you type -list if  
temzzz==0.005-, no cases will be displayed. But if you type -list if  
temzzz<0.005-, your case will be listed. This explains what happens  
next: for Stata, the value of temzzz is smaller than 0.005, which  
yields your result. Further references can be foung in -help  
datatypes- as well, but I work away from my manuals at the moment, so  
I can't help you there. I know other users will be able to do much  
better, but it's a first pointer.

Have a nice day, Chris

On Oct 19, 2005, at 22:30, Jian Zhang wrote:


> Hello,
>
> I have a question about the function int that I could not  
> understand what
> stata is doing.  Hope that you can answer me.  Thanks.
>
> Here it is:
>
> For example, I have a data set:
> id
> 10103005
>
> after I run the following commands:
>
> gen double temxxx=(id/1000)
> gen temyyy=int(temxxx)
> gen temzzz=temxxx-temyyy
> gen areaxxx=int(temzzz*1000)
> list id temxxx temyyy temzzz areaxxx
>
> What I got is
> id         temxxx         temyyy    temzzz  areaxxx
> 10103005   10103.005      10103     .005      4
>
> Is variable areaxxx supposed to be 5? Why did stata give me 4  
> instead of
> 5? Any clue for this?
>
> Thanks.
>
> Jian
>
> *
> *   For searches and help try:
> *   http://www.stata.com/support/faqs/res/findit.html
> *   http://www.stata.com/support/statalist/faq
> *   http://www.ats.ucla.edu/stat/stata/
*
*   For searches and help try:
*   http://www.stata.com/support/faqs/res/findit.html
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/