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Re: st: update from long dataset using criteria
From
Joerg Luedicke <[email protected]>
To
[email protected]
Subject
Re: st: update from long dataset using criteria
Date
Thu, 20 Oct 2011 08:54:44 -0400
Maybe there are neater solutions, but here is one possibility:
1) merge keydate from data1 into data2
2) calculate the difference between test_date and keydate
3) select the record with the smallest difference (within id, and drop the rest)
4) then merge these data with data1 again
HTH,
J.
On Thu, Oct 20, 2011 at 8:33 AM, Colin Campbell
<[email protected]> wrote:
>
> Dear statalist,
>
> I have a master dataset (1) which is a flat file with one record for each unique id. this contains missing data to be updated
> from a second dataset (2) which is in long format with several observations per id.
> I wish to update 1 with the result from 2 where the date difference between keydate(1) and test_date(2) is minimised.
> i.e. for each unique id, update dataset 1 with result and test_date from dataset 2 when criteria X is satisfied
>
> I have managed in dataset 2 to placer test_date in ascending order within each id, reshape wide and keep only the first result
> and then merge, update into the master to import the first result but cannot work out how to apply criteria to this.
>
> Any help appreciated
>
> Colin
>
> dataset 1
>
> IdPacient result test_date keydate
> 1 . . 20/12/2010
> 2 . . 01/01/1999
>
> dataset 2
> IdPacient result test_date _n
> 1 1012 14/07/2010 2
> 1 1008 10/12/2010 3
> 1 779 21/08/2009 1
> 2 231 15/09/1999 3
> 2 195 01/06/1999 2
> 2 197 15/02/1999 1
>
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