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Re: st: Dropping min of two consecutive observations


From   "Rijo John" <rmjohn@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: Dropping min of two consecutive observations
Date   Thu, 13 Nov 2008 15:47:04 -0600

Thanks Jeph. That exactly did the job.

On Thu, Nov 13, 2008 at 3:42 PM, Jeph Herrin <junk@spandrel.net> wrote:
>
> . bys ID (month) : keep if _n==_N
>
>
> should do it.
>
>
>
> Rijo John wrote:
>>
>> Dear Statalist,
>>
>>  I have some repeated observations that I need to drop. I have defined
>> a unique ID variable. There are two other variables "value" and
>> "month" for these IDs.
>>
>> Example data.
>>
>> ID Value  month
>> 1  25        12
>> 1  22         8
>> 2  30         9
>> 3  28         8
>> 3  24         6
>>
>>
>> Only few IDs are repeated in the actual data.
>>
>> Basically I need to retain only one value per ID. If I do "drop if
>> ID==ID[_n-1]" after sorting the IDs it could drop any of the values.
>> But I want the data to retain those values where in month takes the
>> highest value when I am dropping ID==ID[_n-1].  Something like
>>
>> drop min(month, month[_n-1]) if ID==ID[_n-1] is what I am looking for.
>> However, I cant use such time series operators with min function. Any
>> thoughts?
>>
>> Regards,
>> Rijo.
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