qui tab id t
di r(r)
di r(c)
will also work if the number of panels and distinct times are both modest. Be careful if the panels are not balanced.
More generally, check out
SJ-8-4 dm0042 . . . . . . . . . . . . Speaking Stata: Distinct observations
(help distinct if installed) . . . . . . N. J. Cox and G. M. Longton
Q4/08 SJ 8(4):557--568
shows how to answer questions about distinct observations
from first principles; provides a convenience command
The software is accessible to all even if you don't have access to the SJ.
Nick
[email protected]
Maarten buis
Is this what you are looking for:
I assume that your panel identifier is called id
and the time variable t:
// number of periods per person
bys id : gen Nt = _N
// number of person
bys id (t) : gen first = _n == 1
count if first
--- On Fri, 5/6/09, Paulo Regiswrote:
> I am working with a panel, and also need to do some matrix
> operations. The problem is the matrices dimensions depend
> on the T and N dimensions of the panel. Some times, I have
> to drop obs and the dimension may change so I need to
> revise what are the dimensions of the panel. Things are
> even more complicated if I use a do file.
>
> Is there any easy way to do this? I usually work with
> -tsset but, unfortunately, i did not find the way to get
> the dimensions of timevar or panelvar.
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