Re: st: how to write loop program for each value of a variable?

[David Kantor <kantor.d@att.net>]

At 09:28 AM 5/3/2012, Qian wrote:
> Hi, statalist
>      I want to write a loop program for each value of a variable, such as
>      a loop program about variable "v","q", "p" by the value of code(1,2,3),
> the data is listed as following:
> code    v       q       p
> 1       4.65605 3.82133 .5891969
> 1       8.55465 3.273241        .1132121
> 1       .5072982        3.273241        .1132121
> 2       .0668553        3.781385        .112315
> 2       4.346485        3.999861        .1429252
> 2       .453282 3.389864        .27451
> 3       2.514498        2.554792        .432496
> 3       5.027869        3.869841        .1236284
> .       .               .
> .       .       .       .
>
> Then how to write such loop program?
> [...]

You need to tell us more detail about what you want to do. As a 
start, if you really want to write a loop,
you may want to use -levelsof- to gather the set of values of code; 
then use -foreach- to loop over those
values.

But there is a good chance that you don't really need to write a 
loop; your task may be solved by Stata's
implicit looping that occurs in most data-management commands. This 
may also involve the use of the -by-
prefix.

HTH
--David

*
*   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/