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RE: st: how do you drop repeated values in a variable to remain with only one?


From   "Modesto Escobar" <modesto@usal.es>
To   <statalist@hsphsun2.harvard.edu>
Subject   RE: st: how do you drop repeated values in a variable to remain with only one?
Date   Sun, 21 Apr 2013 11:41:31 +0200

Hi, Gwinyai:
Being aware that data will be lost,  I think that you can solve your problem
with this code:
duplicates drop A, force

I hope this works.

Modesto Escobar

-----Mensaje original-----
De: owner-statalist@hsphsun2.harvard.edu
[mailto:owner-statalist@hsphsun2.harvard.edu] En nombre de Gwinyai Masukume
Enviado el: domingo, 21 de abril de 2013 11:18
Para: statalist@hsphsun2.harvard.edu
Asunto: Re: st: how do you drop repeated values in a variable to remain with
only one?

Dear Daniel and Nick,

Thank you. Unfortunately, I could not reproduce the exact variable and
values as patient information must be de-identified.

Along with variable A, there is variable B, C, D, E, which can differ with
the same value of A. I want to remain with a single value of A (I am aware
data will be lost).
I agree 'does not work' is not right. I am the one failing to figure out
things. Please assist.

Kind regards,
Gwinyai

On 4/21/13, Nick Cox <njcoxstata@gmail.com> wrote:
> As the author of -duplicates-, I object strongly to the wording
>
> "does not work"
>
> here.
>
> 1. -duplicates- is designed to allow you to -drop- duplicates when 
> they merely repeat information, so it is entirely a feature that it 
> resists your use here.
>
> 2. The -force- option is nevertheless available to do what you want.
> and is documented in the help.
>
> -force- specifies that observations duplicated with respect to a named 
> varlist be dropped.
>         The -force- option is required when such a varlist is given as 
> a reminder that
>         information may be lost by dropping observations, given that 
> those observations may
>         differ on any variable not included in varlist.
>
> It is, however, a recipe for arbitarily discarding much of the 
> information in your data.
>
>
> Nick
>
> Nick
> njcoxstata@gmail.com
>
>
> On 21 April 2013 07:51, Gwinyai Masukume <parturitions@gmail.com> wrote:
>
>> I have a dataset  with variable A, which has repeated  values:
>>
>> A
>> 1
>> 2
>> 2
>> 2
>> 3
>> 3
>> 4
>> 5
>> 5
>> 6
>> 6
>> 6
>>
>> Where the values are repeated e.g 2. I would like to drop the 
>> repeated values and remain with only a single 2.
>> I have tried the duplicates drop command, but it does not work as the 
>> repeated values are not duplicates, but say different hospital visits 
>> by  the same individual.
>> I would still like to drop repeated values of the variable A. How can 
>> I do this?
>>
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