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st: RE: RE: RE: RE: unique value count in several variables


From   "Nick Cox" <n.j.cox@durham.ac.uk>
To   <statalist@hsphsun2.harvard.edu>
Subject   st: RE: RE: RE: RE: unique value count in several variables
Date   Sun, 19 Jun 2005 13:06:22 +0100

Please remove the "gen" from the last line of the loop. 

Nick 
n.j.cox@durham.ac.uk 

> -----Original Message-----
> From: owner-statalist@hsphsun2.harvard.edu
> [mailto:owner-statalist@hsphsun2.harvard.edu]On Behalf Of Nick Cox
> Sent: 19 June 2005 12:37
> To: statalist@hsphsun2.harvard.edu
> Subject: st: RE: RE: RE: unique value count in several variables
> 
> 
> I too am fond of -levelsof-. For the problem mentioned, 
> this would need to be embedded in a loop over groups, 
> somewhat as follows: 
> 
> gen nvals = . 
> egen group = group(Gvkey year)
> su group, meanonly 
> qui forval i = 1/`r(max)' { 
> 	levelsof psic if group == `i', local(p) 
> 	levelsof ssic if group == `i', local(s)
> 	local total: list s | p
> 	local total:list uniq total
> 	local count:list sizeof total
> 	replace gen nvals = `count' if group == `i' 
> }
> 
> Nick 
> n.j.cox@durham.ac.uk 
> 
> > -----Original Message-----
> > From: owner-statalist@hsphsun2.harvard.edu
> > [mailto:owner-statalist@hsphsun2.harvard.edu]On Behalf Of 
> > Scott Merryman
> > Sent: 19 June 2005 12:30
> > To: statalist@hsphsun2.harvard.edu
> > Subject: st: RE: RE: unique value count in several variables
> > 
> > 
> > In addition to Nick's suggestion of using -reshape-, another 
> > possibility is
> > to use -levelsof- and the macro extended functions (assuming 
> > your cross
> > sections are not too large):
> > 
> > 
> > . l, noobs
> > 
> >   +------------------------------------+
> >   | gvkey   psic   ssic   year   subno |
> >   |------------------------------------|
> >   |  1223   4767   4743   1999       1 |
> >   |  1223   4767   4763   1999       2 |
> >   |  1223   4757   4767   1999       3 |
> >   |  1223   4767   4753   1999       4 |
> >   |  1223   4777   4787   1999       5 |
> >   |------------------------------------|
> >   |  1223   4767   4743   1999       6 |
> >   +------------------------------------+
> > 
> > . levelsof psic, local(p) 
> > 4757 4767 4777
> > 
> > . levelsof ssic, local(s)
> > 4743 4753 4763 4767 4787
> > 
> > . local total: list s | p
> > 
> > . local total:list uniq total
> > 
> > . local count:list sizeof total
> > 
> > . gen nvals = `count'
> > 
> > . l, noobs
> > 
> >   +--------------------------------------------+
> >   | gvkey   psic   ssic   year   subno   nvals |
> >   |--------------------------------------------|
> >   |  1223   4767   4743   1999       1       7 |
> >   |  1223   4767   4763   1999       2       7 |
> >   |  1223   4757   4767   1999       3       7 |
> >   |  1223   4767   4753   1999       4       7 |
> >   |  1223   4777   4787   1999       5       7 |
> >   |--------------------------------------------|
> >   |  1223   4767   4743   1999       6       7 |
> >   +--------------------------------------------+
> > 
> > 
> > Scott
> > 
> > 
> > > -----Original Message-----
> > > From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-
> > > statalist@hsphsun2.harvard.edu] On Behalf Of Wanli Zhao
> > > Sent: Saturday, June 18, 2005 3:17 PM
> > > To: statalist@hsphsun2.harvard.edu
> > > Subject: st: RE: unique value count in several variables
> > > 
> > > Thanks, Nick. I looked into the suggestions and I think I 
> might have
> > > confused you on my problem. My panel data is like this:
> > > Gvkey  psic  ssic  year  subno
> > > 1223   4767  4743  1999  1
> > > 1223   4767  4763  1999  2
> > > 1223   4757  4767  1999  3
> > > 1223   4767  4753  1999  4
> > > 1223   4777  4787  1999  5
> > > 1223   4767  4743  1999  6
> > > 
> > > Using command unique, I can count the distinct values of 
> > psic and ssic by
> > > gvkey by year. So for psic it's 3 and for ssic it's 5. what 
> > I want is to
> > > count the distinct values of both psic and ssic by gvkey by 
> > year. In this
> > > case, it's 7 (4767, 4757, 4777, 4743, 4763, 4753, 4787). 
> > How to generate a
> > > new variable for my purpose? Hope I'm clear now. Pls help.
> > > 
> > > Thanks.
> > > Wanli Zhao
> > > 
> > 
> > 
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> > 
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