Thank you, Ulrich Kohler, Zhiqiang Wang, Martin Wittenberg, for your time in
considering this problem and providing a solution. I found Ulrich's solution
works very well. Brilliant!
Jisheng.
> Generally you should not use foreach to loop over observations. Use -by-
> instead. In your case it is possible to reshape the data to long to do the
> check. Something like this should work:
>
> .. ren person_id id1
> .. ren mother_id id2
> .. reshape long id, i(index) j(idtyp)
> .. sort id idtyp
> .. by id: gen control = idtyp[1]==2 if id~= ""
>
> If your data is ok, the variable "control" should be all zero.
>
> uli
>
>
> Jisheng Cui wrote
>
> > > Following is a sample data with two columns indicating person's ID and
> > mother's ID within a family. I would like to seek the best way to check
> > whether each mother's ID is one of the person's IDs. Otherwise something
> > wrong with the data. Please note: (1) We do not need to check the blank
> > mother's ID.
> > (2) There are some duplicate mother's ID in the family. If a mother's ID
is
> > one of the person's ID, then we skip its duplicates. (3) There are
> > thousands of such families. The program has to be efficient in
calculation.
> > Be ware that -foreach- seems not work with the -by- command.
> >
> > With best wishes,
> >
> > Jisheng.
> >
> >
> > person_id mother_id
> >
> > 042208201006
> > 042208201014
> > 042208201008
> > 042208201099
> > 042208201005
> > 042208201007
> > 042208201097 042208201001
> > 042208201098 042208201001
> > 042208201001 042208201002
> > 042208201094 042208201005
> > 042208201093 042208201005
> > 042208201002 042208201005
> > 042208201095 042208201005
> > 042208201096 042208201005
> > 042208201003 042208201007
> > 042208201009 042208201007
> > 042208201010 042208201007
> > 042208201011 042208201007
> > 042208201013 042208201011
> > 042208201012 042208201011
>
> -
> [email protected]
> http://www.sowi.uni-mannheim.de/lesas
>
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