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Re: st: Listing the first 5 observations


From   Damian Finlayson <damian.finlayson@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: Listing the first 5 observations
Date   Wed, 29 Aug 2012 22:19:48 +0100

Thanks all for your help.

On 29 August 2012 15:31, Nick Cox <njcoxstata@gmail.com> wrote:
> -if- and -in- are completely unrelated. Usually this is a feature, but
> here it means that you have to do some work to get what you want.
>
> One way is
>
> gen OK = age == 49
> sort OK
> l var1 in -5/L
>
> Another way is
>
> browse var1 if age == 49
>
> where in practice you will get a screenful.
>
> I've not been serious about your stipulation of randomness; I guess
> you mean no more than arbitrary.
>
> Note: one criterion; two or more criteria.
>
> Nick
>
> On Wed, Aug 29, 2012 at 3:23 PM, Damian Finlayson
> <damian.finlayson@gmail.com> wrote:
>
>> This seems like a relatively simple query but no matter which way I
>> try I cannot get it to work.
>>
>> I am trying to randomly select a number of observations according a
>> set criteria.
>>
>> Say I have 3 variables: var1, var2 and random.  Var1 consists purely
>> of unique values (such as names).  Var 2 has groups/categories (e.g.
>> age). Random consists of unique random numbers.
>>
>> I would like to get stata to sort each category (age) by a random
>> number and then list the first 5 names for a given age say 49.
>>
>> The command I am trying to use is:
>>
>> list var1 if age == 49
>>
>> but I cannot seem to amend this command so that only the first 5
>> observations  (as per the random number) are listed.  If I use in 1/5
>> it does not work as the first observation for age 49 could be the 53
>> observation the second at 114 and so on.  If I ask for all
>> observations I could end up with thousands of names being listed.
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