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
[email protected]
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: [email protected] [mailto:[email protected]
] Im Auftrag von "SERGIO M. AFCHA CHÁVEZ"
Gesendet: Mittwoch, 29. April 2009 17:55
An: [email protected]
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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