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AW: st: Question


From   "Martin Weiss" <martin.weiss1@gmx.de>
To   <statalist@hsphsun2.harvard.edu>
Subject   AW: st: Question
Date   Tue, 21 Apr 2009 09:22:02 +0200

<> 

That blank after "firm_name" in " firm_name [`i']" could hurt you. Consider
the difference:

*************
sysuse auto, clear

//w/o blank
forv i=1/5{
	di in red mpg[`i']
}

//with blank
forv i=1/5{
	di in red mpg [`i']
}
*************

If the initial poster (cannot find his name) could post an extract from his
dataset, I am pretty sure the loop will be rendered redundant...


HTH
Martin

-----Ursprüngliche Nachricht-----
Von: owner-statalist@hsphsun2.harvard.edu
[mailto:owner-statalist@hsphsun2.harvard.edu] Im Auftrag von Gao Liu
Gesendet: Dienstag, 21. April 2009 08:18
An: statalist@hsphsun2.harvard.edu
Betreff: Re: st: Question

Dear Zhu, Yi:

Here is one way:

sort firm_name alliance_date

qui forval i = 1/`=_N' {
	count if firm_name  == firm_name [`i'] &
inrange(alliance_date-alliance_date[`i'] , 1, (5*365+1))
	replace alliance_no= r(N) in `i'
}


It may take a while, as it has to run through all observations one by
one, but it should work.

Best

Gao



2009/4/21 朱琦 <cs_thomaszhu@hotmail.com>
>
> Question
>
> Dear Stata List!
>
> I am working on a project that examines a firm's international strategic
alliance (ISA).
>
> In my huge dataset, I have around 2000 firms forming ISA between
01/01/1989- 0/01/1999. Each firm is likely to form multiple international
strategic alliances during this period.
> For example: Firm A  forms the first strategic alliance on 01/02/1989; the
second on 04/09/1990; the third on 06/09/1997.
>
> What I need to record is the number of new strategic alliances that the
firm forms within 5 years after the focal one.
> For firm A, the number of new strategic alliances that Firm A forms within
5 years is 1 corresponding to its first strategic alliance on  01/02/1989;
>                 the number of new strategic alliances that Firm A forms
within 5 years is 0 corresponding to  its second strategic alliance on
04/09/1990 ;
>                the number of new strategic alliances that Firm A forms
within 5 years is 0 corresponding to  its third strategic alliance on
06/09/1997;
>
> As it is a huge dataset, I can't do it by hand. How can I do it by using
STATA? Thanks!
>
>
>
> *
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> *   http://www.ats.ucla.edu/stat/stata/

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