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RE: st: looping over parallel lists - is there a alternative to "for"?


From   "Nick Cox" <n.j.cox@durham.ac.uk>
To   <statalist@hsphsun2.harvard.edu>
Subject   RE: st: looping over parallel lists - is there a alternative to "for"?
Date   Thu, 16 Mar 2006 11:51:57 -0000

As has been said, -for- divides the world (like 
Marmite, if you know what that is). 

The two camps are, naturally, "for" and "against". 

Once you have seen the light on -forvalues- and -foreach-, 
you never want to go back. 

Nick 
n.j.cox@durham.ac.uk 

Ada Ma
 
> I suppose you can have three globals and then have one loop to loop
> through them?  Some samples can be found in C Baum's "A little bit of
> Stata programming goes a long way ..."
> 
> http://www.stata.com/meeting/11uk/baum.pdf
> 
> I quite like the -for- command as well, sometimes I only want to loop
> one line of command and using commands like -forvalue- and -foreach-
> gets a bit complicated.  And speaking for myself, using -for- would
> save me from making typos like using ) instead of }.
> 
> 
> 
> On 3/16/06, Gawrich Stefan <s.gawrich@hlpug.hessen.de> wrote:
> > Hi,
> >
> > I do a lot of routine or repetitive data analysis and use 
> loops and lists
> > frequently (btw, thx to Nick Cox, his "How to fact lists 
> with fortitude"
> > helped me a lot).
> >
> > I'm wondering why the "for"-command is officialy out of 
> date in Stata while
> > one of it's best features  - the use of parallel lists - 
> can't be done
> > otherwise. Or am I missing something?
> >
> > One example: I routinely map ten different diseases with 
> tmap and save the
> > maps as a graphic file.
> >
> > for var var1-var10 \ any "Disease1" "Disease2" [...] \ any 
> "Filename1"
> > "Filename2" [...] : ///
> > tmap choro X, id(county) map("county-Coordinates.dta") 
> title("Y") \ graph
> > export "Z.png", replace
> >
> > In this example each graph is determined by something like 
> a 3-tuple of
> > variable, title and saving-filename.
> > This is just basic code, in real life the code blows up and 
> becomes hard to
> > read, as we all know, "for" has some disadvantages.
> > So if it can be done in a more structured manner, I would 
> like to know...

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