Re: st: AW: Merging database

["Eric A. Booth" <ebooth@ppri.tamu.edu>]

Additionally, if Sergio is concerned about identifying which dataset  
the observation came from after his merge,  using the -joinby- command  
with the _merge() option might be useful.

something like:

 joinby V using "filename", unmatched(both) _merge(label)




~Eric


__
Eric A. Booth
Public Policy Research Institute
Texas A&M University
ebooth@ppri.tamu.edu
Office: +979.845.6754
Fax: +979.845.0249
http://ppri.tamu.edu



On Apr 29, 2009, at 11:41 AM, Eric A. Booth wrote:

> To add to Jochen's comment:
>
> If you were hoping to have a new 'ID' variable that keeps the  
> information from all the ID variables V1, V2, and V3, you could  
> create a string variable...here are some examples:
>
> ******************
>
> clear
> input V1  V2  V3
> 1     .       1
> 2     .       2
> 3    3       3
> 4    4        .   .     5       5
> 6     .       6
> end
> //
> foreach x in V* {
> 	recode `x' (.=99)  // <-- So that -regexr- isn't tripped up later
> 	tostring `x', replace
> 	}
> 	gen str10 v_combined = V1+"_"+V2+"_"+V3
> 	gen v_combined2 = regexr(v_combined, "99", "x")
> 	sencode v_combined2, gene(uniqueID) gsort(+v_combined2) label(id)	
> list
>
> ******************
>
>
> ~Eric
>
>
> __
> Eric A. Booth
> Public Policy Research Institute
> Texas A&M University
> ebooth@ppri.tamu.edu
> Office: +979.845.6754
> Fax: +979.845.0249
> http://ppri.tamu.edu
>
> On Apr 29, 2009, at 11:36 AM, Jochen Späth wrote:
>
> > Hello Sergio,
> >
> > I'm not quite sure of what your problem is, maybe it would help if  
> > you were a little more precise.
> >
> > Below, I assumed that the example you gave is AFTER your three data  
> > sets have been merged, with v1 coming from the first, v2 from the  
> > second and v3 from the third and with v1, v2 and v3 denoting all  
> > the same ID. If this is the case you could
> >
> > -replace v1 = v2 if v1 == . & v2 != .-
> > -replace v1 = v3 if v1 == . & v2 ==. & v3 != .-
> > -count if v1 == .- /* should return 0, otherwise there are  
> > observations in your data that are not uniquely determined by  
> > either of your three ID variables.*/
> > -drop v2 v3- /* of course, only if you got all IDs caught in v1 */
> >
> > HTH,
> > Jochen
> >
> > -----Ursprüngliche Nachricht-----
> > Von: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu 
> > ] Im Auftrag von "SERGIO M. AFCHA CHÁVEZ"
> > Gesendet: Mittwoch, 29. April 2009 17:55
> > An: statalist@hsphsun2.harvard.edu
> > Betreff: st: Merging database
> >
> > Dear Statlisters,
> >
> > I have a little problem merging a data base. I have variables for 3
> > years showing an ID:
> >
> >
> > V1  V2  V3
> > 1     .       1
> > 2     .       2
> > 3    3       3
> > 4    4        .
> > .     5       5
> > 6     .       6
> >
> >
> > I need only one ID variable. How can I obtain one column with  all  
> > the
> > ID numbers?
> >
> > Thanks in advance for your help.
> >
> > Sergio
> >
> >
> > *
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