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st: RE: programming in Stata
--- 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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