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Re: st: RE: Merge Question


From   Nick Winter <nw53@cornell.edu>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: RE: Merge Question
Date   Fri, 05 Nov 2004 14:01:11 -0500

To elaborate: I think you need to use Nick's approach to finding the most common values in dataset2, then -keep- only those lines, save that as dataset3, and then merge dataset3 into dataset1.

--Nick Winter




At 06:42 PM 11/5/2004 +0000, you wrote:

Your most common values can be obtained by

bysort code1 code2 : gen count = - _N    [!!! NB - ]
bysort code1 (count code2) : gen mode = code2[1]

Nick
n.j.cox@durham.ac.uk

Jason Hwang

> I didn't describe very well last time what I wanted to do. Let me try
> again.
>
> I have two datasets I'm trying to merge of the following form.
>
> dataset1:
>
> code1 output
> 1111  100
> 5555  340
>
> dataset2:
>
> code2 pchange code1
> 3431  .5      1111
> 3431  .5      1111
> 3450  -.5     1111
> 3451  .7      1111
> 9903  .4      5555
> 9945  .1      5555
> 9903  .4      5555
> 9905  -.6     5555
> 9945  .1      5555
>
> I'm trying to use dataset1 as the original (master) and merge into it
> dataset2. Problem: each code1 maps to many code2s. So here's
> what I would
> like to do: for each code1, find a code2 which corresponds to
> it with the
> greatest frequency. So for code1, 1111, I want 3431. For
> 5555, both 9903
> and 9945 occur twice. In this case, I'll just take whichever shows up
> first in the sorted list; i.e. 9903.
>
> The final output I'm looking for would be:
>
> code1 code2   output  pchange
> 1111  3431    100     .5
> 5555  9903    340     .4
>
> Could some one how to write a code for this procedure? Thank you very
> much.

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--------------------------------------------------------
Nicholas Winter 607.255.8819 t
Assistant Professor 607.255.4530 f
Department of Government nw53@cornell.edu e
308 White Hall falcon.arts.cornell.edu/nw53 w
Cornell University
Ithaca, NY 14853-4601

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