[email protected]
>
> To recap this thread: In response to my posting where I
> expressed my wish
> to avoid explicit looping over observations to create a
> value label mapping
> between a numeric variable and a string variable, Michael
> Blasnik suggested
> the following approach:
< snip >
>
> Nick Cox had previously suggested
< snip >
>
> To compare the relative efficiency of both solutions, I put
> together two
> separate routines, one using the -forvalue- approach, the
> other using the
> -outsheet- line. I then compared their relative
> performance (see table
> below).
< snip >
>
> maplab2 turned out to be much faster! It's running the .do
> file in in
> maplab1 which is time consuming. Here's a quick tabulation
>
> seconds elapsed
> ----------
> obs ('000s) maplab1 maplab2
> ------------+----------------------
> 1 | .3 .2
> 3 | 1.1 1.3
> 5 | 4.7 2.7
> 7 | 11.6 4.2
> 9 | 21.8 5.6
> 30 | 300.3 21.2
>
> where we have a different value label for each observation.
>
> I'll go with maplab2 then. Thanks all.
>
I'll add two comments: one is trivial
and the other is less so.
1. Anyone wanting to copy Patrick's program -maplab2-
should note that he has left wired into three lines
his original variable names
> local val = naics[`i']
> local label = labelnaics[`i']
> label def naicslab `val' "`label'" , modify
The correction is just to generalise to use `1', `2'
and `labname'.
2. The results seem fairly clearcut, but I'll repeat an
earlier caution that even relative timings dependent on I/O can
vary according to machine, OS and set-up (e.g.
whether you are using Stata on your "own" machine
or over a network). In preparing an FAQ on a different
question which is at
http://www.stata.com/support/faqs/data/savesome.html
and trying to distill which method of two was faster,
Paul Seed, Jean Marie Linhart and I found what were
to me surprising contradictions, with my "own" Stata 7 under
Windows XP being the odd one out.
Nick
[email protected]
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