If you put these values into a matrix,
you will just create a problem for later
of how to extract them, especially for
plotting.
You should be aware of -collapse-
and -egen, tag()-. The former cuts
out the repeated storage, at the
cost of losing other data that may be
interesting or important. The latter
lets you select just one of every
group so that graphs are not based
on the same information repeated
several times.
Nick
n.j.cox@durham.ac.uk
Jonas Dovern
> I have the following problem with regard to efficient
> programming/data storing:
>
> Assume I have a data in stacked form, e.g.:
>
> Country Year Var1
> A 1 q
> A 2 w
> A 3 e
> A 4 r
> A 5 t
> B 1 z
> B 2 u
> B 3 i
> B 4 o
> . . .
> . . .
> . . .
> C 5 p
>
> What I want is to compute the average across countries of
> Var1 for each
> year - and store these values to make a plot later on. So far
> I created a
> new variable, say Mean, and filled it with the mean values. The new
> variable, however, is also of size #Counties*#Years repeating
> the entries
> for each year #Countries-times -- although I would need to
> store the mean
> for each year only once.
>
> What is the usual way to perform this task? Store the values
> in a matrix?
> Can I easily plot this matrix later on?
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