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Re: st: How to transfer a variable's value into a macro (in a panel dataset)


From   Gregory Branch <greg_branch@gfbonline.org>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: How to transfer a variable's value into a macro (in a panel dataset)
Date   Sat, 26 Feb 2005 06:03:29 -0800 (PST)

I haven't spent a lot of time thinking about this, but
it might be more efficient to take a slightly
different tack on this. Something like the following
might work:

1) Make a second copy of your data set.  
2) Generate a column of "1"s
3) reshape wide, i = year, j = firm, xij = whatever
you called the column of ones.
4) merge back onto the original dataset by year.

Best of luck

Greg Branch
Research Scientist,
UT Dallas/Texas Schools Project


--- Robin Luo <rluosf@gmail.com> wrote:

> Sorry for the confusion. Let me explain the
> situation in more details:
> 
> I have a variable called "firmid" and I generate a
> set of dummy
> variables from it. Now I need to use the value of
> the varialbe
> "firmid" to locate the dummy variables and do some
> calculations but
> the location part confuses me. Basically, my data
> has the following
> structure:
> 
> firmid   year      firm_100 firm_101 firm_102
> firm_103 firm_104 ......
> 100      1980 
> 101      1980
> 105      1980
> 121      1980
> 124      1980
> 101      1981
> 103      1981
> 196      1981
> 
> The data has been sorted by year and my goal is to
> check in each year
> which firms co-exist with a certain firm - for those
> coexisting, their
> respective dummy variables will be changed to 1
> accordingly. For
> example, firm 100, 101, 105, 121, 124 coexist in
> 1980. Therefore, for
> the record where firmid=100 and year=1980, variables
> firm_101,
> firm_105 and likewise will be changed to 1. My plan
> is that for each
> year group check the values of "firmid" and then
> output these values
> to a local macro, which can be used to locate the
> corresponding firm
> dummy variables. But, as stated in my firm mail, I
> was stuck in how to
> do this macro set-up in a groupwise environment.
> 
> Many thanks!
> 
> Robin Luo
> 
> On Sat, 26 Feb 2005 00:44:34 +0000, Ada Ma
> <pec187@abdn.ac.uk> wrote:
> > you can't use -by- for setting locals because you
> can only have one value for
> > each local value.  i can only equals to one thing,
> it's not like a variable in
> > the dataset which can carry multiple values.
> > 
> > what are you trying to do anyway?  if you tell us
> what you're actually trying to
> > do then may be someone can work out the solution
> for you.
> > 
> > 
> > Robin Luo wrote:
> > 
> > > I know that a command like:
> > >
> > > local i = var[`n']
> > >
> > > can obtain the nth observation's value into
> macro i. But my data is a
> > > panel data and I want the nth observation within
> a certain group into
> > > the macro i, instead of that of the nth
> observation in general.
> > > Obviously, "local" cannot be used with "by" and
> I could not figure out
> > > a way to do this. If any one has any idea on
> this, I would really
> > > appreciate.
> > >
> > > Thanks!
> > >
> > > Robin Luo
> > 
> > *
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