Re: st: RE: programming in Stata

[Antoine Terracol <Antoine.Terracol@univ-paris1.fr>]

Are you sure you correctly specified the -bysort- part of the command ?

Ali Khashan wrote:
> Many Thanks to those who responded.
> The suggested commands work but they are not enough. They do not take into
> account that we have different mothers. for example for mother_number
> 1234567892 newvar will be 40 when it must be missing because this mother 
> has no
> previuos child. Is there another code to work only when the 
> mother_number is
> repeated.
>
> Many Thanks
> Ali
>
>
> Quoting Maarten Buis <M.Buis@fsw.vu.nl>:
>
>
> > --- Ali Khashan wrote:
> > > I have a large dataset similar to this:
> > > mother_number         child_number  GA     nDate            suggested 
> > > var
> > > 1234567891            23456789      35     21 Feb 1975       .
> > > 1234567891            23456781      37     30 May 1978       35
> > > 1234567891            23456782      40     04 Oct 1982       37
> > > 1234567892            56789012      37     17 Mar 1976
> > > 1234567893            56489023      40     23 Sep 1985
> > > 1234567894            34567891      40     19 Nov 1977
> > > 1234567894            45567890      42     13 May 1979
> > >
> > > From mother_number you can see that some women have more than one 
> > > child (they
> > > have the same identification number). GA is gestational age and nDate 
> > > is date
> > > of birth of the child. I need to generate another variable which 
> > > indicates
> > > gestational age of the previuos child.
> >
> > *---------------------- begin example ------------
> > clear
> > input double mother_number double child_number GA
> > 1234567891            23456789      35
> > 1234567891            23456781      37
> > 1234567891            23456782      40
> > 1234567892            56789012      37
> > 1234567893            56489023      40
> > 1234567894            34567891      40
> > 1234567894            45567890      42
> > end
> >
> > bys mother_number (GA): gen prevGA = GA[_n-1]
> > list
> > *-------------------- end example -------------------
> > (For more on how to use examples I sent to the Statalist, see
> > http://home.fsw.vu.nl/m.buis/stata/exampleFAQ.html )
> >
> > -----------------------------------------
> > Maarten L. Buis
> > Department of Social Research Methodology
> > Vrije Universiteit Amsterdam
> > Boelelaan 1081
> > 1081 HV Amsterdam
> > The Netherlands
> >
> > visiting address:
> > Buitenveldertselaan 3 (Metropolitan), room Z434
> >
> > +31 20 5986715
> >
> > http://home.fsw.vu.nl/m.buis/
> > -----------------------------------------
> >
> >
> >
> > *
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> > *   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:
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