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From |
"Wanli Zhao" <zhaowl@temple.edu> |

To |
<statalist@hsphsun2.harvard.edu> |

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

Date |
Sun, 19 Jun 2005 17:26:35 -0400 |

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/

**References**:**st: RE: RE: RE: RE: unique value count in several variables***From:*"Nick Cox" <n.j.cox@durham.ac.uk>

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