Thursday, March 16, 2006

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

I don't like marmite (don't mind it either). I kind of think of it as English miso... hahaha.

About the "for" and "against" camps - I kind of sit on the fence because although I almost always use -foreach- and -forval-, every once in a while I'd slip in a -for- for one-liners. I believe I'm very far from fully exploiting the potentials of -forval- and -foreach- so that could explain my preference.

On 3/16/06, Nick Cox <n.j.cox@durham.ac.uk> wrote: > 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... > > * > * For searches and help try: > * http://www.stata.com/support/faqs/res/findit.html > * http://www.stata.com/support/statalist/faq > * http://www.ats.ucla.edu/stat/stata/ >

-- Ada Ma Research Fellow Health Economics Research Unit University of Aberdeen, UK. http://www.abdn.ac.uk/heru/ Tel: +44 (0) 1224 553863 Fax: +44 (0) 1224 550926

* * For searches and help try: * http://www.stata.com/support/faqs/res/findit.html * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/


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