st: Re: a question on function int

["Michael Blasnik" <michael.blasnik@verizon.net>]

It has nothing to do with the int() function, it has to do with precision. 
temzzz does not contain .005, but instead 0.0049999998882....  Try -search 
precision- and check out the various FAQs at the end to learn more.   You 
can sometimes address these problems by using doubles instead of floats.  In 
other cases you can use the float() function and sometimes just using 
round() works.  In your case, I would keep long integer IDs as string 
variables to avoid precision issues and allow easier access to extracted 
segments.

Michael Blasnik
michael.blasnik@verizon.net

----- Original Message ----- 
From: "Jian Zhang" <jzh@ucdavis.edu>
To: <statalist@hsphsun2.harvard.edu>
Sent: Wednesday, October 19, 2005 4:30 PM
Subject: st: a question on function int



> 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
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