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Re: st: The accuracy of the float data type
From
Maarten Buis <[email protected]>
To
[email protected]
Subject
Re: st: The accuracy of the float data type
Date
Fri, 24 Jan 2014 17:23:41 +0100
I would do this differently:
*------------------ begin example ------------------
// get some example data
sysuse auto
// create a variable denoting missing values
gen byte miss = missing(rep78, price)
// create our indicator variable
bys rep78 miss (price) : gen max = _n == _N if !miss
// admire the result
list rep78 miss price max in 1/12, sepby(rep78)
*------------------- end example -------------------
* (For more on examples I sent to the Statalist see:
* http://www.maartenbuis.nl/example_faq )
Hope this helps,
Maarten
On Fri, Jan 24, 2014 at 4:53 PM, R Zhang <[email protected]> wrote:
> Dear Statalist,
>
> my data structure is as follows
>
> firmID segmentID sales year
> 1001 1 25.395 1990
> 1001 1 32.007 1991
>
> ............
>
> a firm can operate in multiple segments as identified by segmentID .
> I wanted to identify the largest segment by sales,so I used
>
> bysort firmID year : egen maxsale=max(sales)
>
> then I did
> gen PriSIC=0
> replace PriSIC=1 if sales=maxsale
>
> I got
> firmID segmentID sales year maxsale prisic
> 1001 1 25.395 1990 25.395 0
> 1001 1 32.007 1991 32.007 0
>
> I could not figure out why prisic is 0, so I compute the diffderence
> (sales-maxsale), it shows a very small negative number , and the data
> dictionary shows sales format float %12.0g, and maxsale format float
> %9.0g
>
> what should I do to correct this?
>
> thanks!!!
>
> Rochelle
> *
> * For searches and help try:
> * http://www.stata.com/help.cgi?search
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--
---------------------------------
Maarten L. Buis
WZB
Reichpietschufer 50
10785 Berlin
Germany
http://www.maartenbuis.nl
---------------------------------
*
* For searches and help try:
* http://www.stata.com/help.cgi?search
* http://www.stata.com/support/faqs/resources/statalist-faq/
* http://www.ats.ucla.edu/stat/stata/