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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 |
Mon, 20 Jun 2005 00:48:06 +0100 |

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 n.j.cox@durham.ac.uk > -----Original Message----- > From: owner-statalist@hsphsun2.harvard.edu > [mailto:owner-statalist@hsphsun2.harvard.edu]On Behalf Of Wanli Zhao > Sent: 20 June 2005 00:08 > To: statalist@hsphsun2.harvard.edu > 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: owner-statalist@hsphsun2.harvard.edu > [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Nick Cox > Sent: Sunday, June 19, 2005 5:54 PM > To: statalist@hsphsun2.harvard.edu > 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 > n.j.cox@durham.ac.uk > > 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: owner-statalist@hsphsun2.harvard.edu > > [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Nick Cox > > Sent: Sunday, June 19, 2005 8:06 AM > > To: statalist@hsphsun2.harvard.edu > > Subject: st: RE: RE: RE: RE: unique value count in several variables > > > > 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 > > > > > > > > > > > > > > > > > * > > > > * For searches and help try: > > > > * http://www.stata.com/support/faqs/res/findit.html > > > > * http://www.stata.com/support/statalist/faq > > > > * http://www.ats.ucla.edu/stat/stata/ > > > > > > > > > > * > > > * For searches and help try: > > > * http://www.stata.com/support/faqs/res/findit.html > > > * http://www.stata.com/support/statalist/faq > > > * http://www.ats.ucla.edu/stat/stata/ > > > > > > > * > > * For searches and help try: > > * http://www.stata.com/support/faqs/res/findit.html > > * http://www.stata.com/support/statalist/faq > > * http://www.ats.ucla.edu/stat/stata/ > > > > > > * > > * For searches and help try: > > * http://www.stata.com/support/faqs/res/findit.html > > * http://www.stata.com/support/statalist/faq > > * http://www.ats.ucla.edu/stat/stata/ > > > > * > * For searches and help try: > * http://www.stata.com/support/faqs/res/findit.html > * http://www.stata.com/support/statalist/faq > * http://www.ats.ucla.edu/stat/stata/ > > > * > * For searches and help try: > * http://www.stata.com/support/faqs/res/findit.html > * http://www.stata.com/support/statalist/faq > * http://www.ats.ucla.edu/stat/stata/ > * * For searches and help try: * http://www.stata.com/support/faqs/res/findit.html * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

**Follow-Ups**:**st: RE: time effects estimation in panel commands?***From:*"Wanli Zhao" <zhaowl@temple.edu>

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