Many Thanks to Nick & Eric...
--clint
>>> [email protected] 9/9/2004 11:33:34 AM >>>
A slightly more general approach can be based
on variables generated with -egen, seq()- and/or
-egen, fill()-.
Nick
[email protected]
Eric G. Wruck
> Clint Thompson wrote:
>
> >I want to sort then keep every 5th observation, of a
> fictitious dataset. Aside from going into the data editor
> and manually deleting observations one-by-one (or using a
> series of drop/keep commands), is there a more elegant way to
> do this?? My initial idea was to generate a new variable using the
> >_n system variable then keeping only those observations
> divisible by, say, five. Example:
> >
> >sort varname
> >gen obsno = _n
> >keep if (obsno/5)
>
>
> Here's a quick example using the mod() function available in Stata:
>
> . l
>
> +----+
> | y |
> |----|
> 1. | 20 |
> 2. | 24 |
> 3. | 28 |
> 4. | 32 |
> 5. | 46 |
> |----|
> 6. | 36 |
> 7. | 40 |
> 8. | 44 |
> 9. | 48 |
> 10. | 52 |
> +----+
>
> . keep if mod(_n,5) == 0
> (8 observations deleted)
>
> . l
>
> +----+
> | y |
> |----|
> 1. | 46 |
> 2. | 52 |
> +----+
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