# Re: st: A query about sorting.

 From "Ashim Kapoor" <[email protected]> To [email protected] Subject Re: st: A query about sorting. Date Mon, 25 Aug 2008 18:06:26 +0530

```gen v2 = -v /*to sort from highest to lowest*/
bys i (v2): gen var = _n

What do the above 2 lines do Maarten?

Thank you,
Ashim.

On Mon, Aug 25, 2008 at 5:58 PM, Maarten buis <[email protected]> wrote:
> --- Ashim Kapoor <[email protected]> wrote:
>> I have a simple code to write.
>>
>> I have 6 variables v1, v2 , v3, v4 ,v5 , v6.
>>
>> I want to sort "according to each observation". That is , in the end
>> for each i I want , v1[i] < = v2[i] <=... v6[i].
>>
>> So I wrote a simple bubble for each row and then loop from 1 to _N.
>>
>> Now the problem is that this works but it's VERY VERY slow.
>
> This could be done using a combinatin of -reshape- and -by-, like in
> the example below. This should be faster.
>
> *--------------- begin example ---------------
> // create some random data
> drop _all
> set obs 10
> forvalues i = 1/3 {
>        gen v`i' = floor(10*uniform())
> }
>
> // do the sort
> list
> gen i = _n
> reshape long v, i(i) j(var)
> drop var
> gen v2 = -v /*to sort from highest to lowest*/
> bys i (v2): gen var = _n
> drop v2
> reshape wide v, i(i) j(var)
> drop i
> list
> *----------------- end example ----------------
> (For more on how to use examples I sent to the Statalist, see
> http://home.fsw.vu.nl/m.buis/stata/exampleFAQ.html )
>
> Hope this helps,
> Maarten
>
> -----------------------------------------
> Maarten L. Buis
> Department of Social Research Methodology
> Vrije Universiteit Amsterdam
> Boelelaan 1081
> 1081 HV Amsterdam
> The Netherlands
>
> Buitenveldertselaan 3 (Metropolitan), room Z434
>
> +31 20 5986715
>
> http://home.fsw.vu.nl/m.buis/
> -----------------------------------------
>
> Send instant messages to your online friends http://uk.messenger.yahoo.com
> *
> *   For searches and help try:
> *   http://www.stata.com/help.cgi?search
> *   http://www.stata.com/support/statalist/faq
> *   http://www.ats.ucla.edu/stat/stata/
>
*
*   For searches and help try:
*   http://www.stata.com/help.cgi?search
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/
```