Quite so. -levels- was introduced as an official command during the
lifetime of Stata 8, and so was not documented in the Stata 8 manuals.
In Stata 9,
-levelsof- was introduced and put out in front, although -levels-
continues to work, as is true in Stata 10. The two are thus different
names for the same command in Stata 9 and 10.
For the future, note this advice in the FAQ: "The current version of
Stata is 10. Please specify if you are using an earlier version;
otherwise, the answer to your question is likely to refer to commands or
features unavailable to you."
Nick
[email protected]
Peter Dijkstra
Thanks Maarten, everything is clear now! Although I have Stata8.2SE it
gave me an idea what keyword to look for. So for all Stata8 users:
*--------------- begin example -------------------
sysuse auto, clear
recode rep78 1/2 = 3
levels rep78
foreach lev in `r(levels)' {
di _n _n as txt "rep78 = " as result `lev'
reg mpg wei if rep78 == `lev'
}
*---------------- end example --------------------
-------- Original-Nachricht --------
> Datum: Thu, 14 Feb 2008 09:46:48 +0000 (GMT)
> Von: Maarten buis <[email protected]>
> An: [email protected]
> Betreff: Re: st: Loop over all unique values of a variable
> --- Maarten buis <[email protected]> wrote:
> > -statsby- may also be convenient. It not performs those regressions
> > it also collects the results in a new dataset
>
> I meant:
> It not only performs those regressions but it also collects the
results
> in a new dataset.
*
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