Re: st: Merging two datasets multiple times

[Maarten buis <maartenbuis@yahoo.co.uk>]

--- On Wed, 7/4/10, Pavlos C. Symeou wrote:
> I have two datasets (A and B) which I need to merge.
<snip>
> Basically, for every patent I want to have all its IPCs and
> all SICs in the same row.

A combination of -reshape- and -merge- may be the easiest solution
here:

*--------------------------- begin example -----------------------
// create some example data
clear
input id   str4 ipc_1  str4 ipc_2
      1         AAAA        BBBB
      2         AAAA        CCCC
      3         DDDD        CCCC
end

tempfile a
save `a'

clear 
input str4 ipc    str6 sic_1    str6 sic_2    str6 sic_3
           AAAA        zzzzz         xxxxx         yyyyyy 
           BBBB        tttttt        rrrrrr        ooooo  
           CCCC        www           gggg          pppp   
           DDDD        foo           bar           bla
end
tempfile b
save `b'

// the actual answer
use `a'
reshape long ipc_, i(id) j(destination)
rename ipc_ ipc
save `a', replace

use `b'
merge 1:m ipc using `a'
assert _merge == 3
drop _merge

rename ipc ipc_
rename sic_1 sic_1_
rename sic_2 sic_2_
rename sic_3 sic_3_

reshape wide ipc_ sic_1_ sic_2_ sic_3_, i(id) j(destination)
list
*--------------------- end example --------------------------
(For more on examples I sent to the Statalist see: 
http://www.maartenbuis.nl/example_faq )

Hope this helps,
Maarten

--------------------------
Maarten L. Buis
Institut fuer Soziologie
Universitaet Tuebingen
Wilhelmstrasse 36
72074 Tuebingen
Germany

http://www.maartenbuis.nl
--------------------------


      

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