My statement about -nvals- existing when you
tried -reshape- was based on the output you
quote below.
I'm pleased that you have solved your problem.
Nick
[email protected]
> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]]On Behalf Of Wanli Zhao
> Sent: 20 June 2005 00:08
> To: [email protected]
> Subject: st: RE: RE: RE: unique value count in several variables
>
>
> Nick,
> I do not have nvals beforehand. I finally modified your
> "reshape" program as
> I did manually in Eviews and it worked. I just replace the
> missing values
> with some number (I put 99) and run your program and the
> nvals shows the
> right number (of course it includes missing value as a
> distinct sic). So the
> only complication in my case is the missing value needs to be
> a number.
> Thanks again.
>
> Wanli
>
> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]] On Behalf Of Nick Cox
> Sent: Sunday, June 19, 2005 5:54 PM
> To: [email protected]
> Subject: st: RE: RE: unique value count in several variables
>
> Scott's program does not claim to subdivide by your key and
> year and it does
> not do so.
>
> What you call "Nick's original program" appears to be my first code as
> modified by you. It was based on the idea that -nvals- did not exist
> beforehand, and indeed the purpose of the code is to create
> -nvals-. In your
> case, you appear to have used it after creating -nvals- in
> some other way.
> That won't work. At a minimum, you need to drop -nvals- first.
> It is possible also that complications you didn't tell us
> about have not
> been taken into account in modifying the code, as you are here using
> variable names not previously explained.
>
> Naturally, people often simplify their problem for Statalist
> to show the
> essence of it. That's great for the people who answer the questions.
> However, the original posters then need to add back the
> complications in
> exactly the right way.
>
> Otherwise put, there is nothing in this report that looks to
> me like a bug
> in Scott's code or mine given the original example you specified.
>
> You are right that the second approach will be slower than the first.
> There's a lot of looping and testing -if-.
>
> Nick
> [email protected]
>
> Wanli Zhao
>
> > I feel I need to report on my running for people interested.
> > I have a large
> > panel, about 1600 cross-section and 11 years. Scott's program
> > generates nvals variable with a single value 1005 ( I do
> not know what
> > it means) for all the gvkey-year. Nick's modification seems
> to work.
> > The problem is the time is unacceptable. I broke the
> program and the
> > values seem correct for finished part.
> > Nick's original "reshape" program also gave me an error message as
> > follows:
> > [reshape error
> > (note: j = ssic1 ssic2)
> > i (gvkey year sid) indicates the top-level grouping such as subject
> > id.
> > j (_j) indicates the subgrouping such as time.
> > xij variable is K.
> > Thus, the following variable(s) should be constant within i:
> > nvals
> > nvals not constant within i (gvkey year sid) for 28662 values of i:]
> >
> > I guess the problem is that my ssic1 and ssic2 have many missing
> > values.
> > Thanks.
> >
> > Wanli Zhao
> >
> >
> > -----Original Message-----
> > From: [email protected]
> > [mailto:[email protected]] On Behalf Of Nick Cox
> > Sent: Sunday, June 19, 2005 8:06 AM
> > To: [email protected]
> > Subject: st: RE: RE: RE: RE: unique value count in several variables
> >
> > Please remove the "gen" from the last line of the loop.
> >
> > Nick
> > [email protected]
> >
> > > -----Original Message-----
> > > From: [email protected]
> > > [mailto:[email protected]]On Behalf Of Nick Cox
> > > Sent: 19 June 2005 12:37
> > > To: [email protected]
> > > 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
> > > [email protected]
> > >
> > > > -----Original Message-----
> > > > From: [email protected]
> > > > [mailto:[email protected]]On Behalf Of Scott
> > > > Merryman
> > > > Sent: 19 June 2005 12:30
> > > > To: [email protected]
> > > > 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: [email protected] [mailto:owner-
> > > > > [email protected]] On Behalf Of Wanli Zhao
> > > > > Sent: Saturday, June 18, 2005 3:17 PM
> > > > > To: [email protected]
> > > > > 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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