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


From   Nick Cox <njcoxstata@gmail.com>
To   "statalist@hsphsun2.harvard.edu" <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 09:43:55 +0100

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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