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AW: st: AW: Quotes for scalar within local (was efficiently run three loops (or do without them))


From   "Martin Weiss" <martin.weiss1@gmx.de>
To   <statalist@hsphsun2.harvard.edu>
Subject   AW: st: AW: Quotes for scalar within local (was efficiently run three loops (or do without them))
Date   Tue, 14 Apr 2009 09:41:53 +0200

<> 

The line -g x = foreign == `i' & rep78 == `j'- smacks of 

*************
egen mygroups=group(for rep)
*************

as a more easily intelligible alternative...


HTH
Martin


-----Ursprüngliche Nachricht-----
Von: owner-statalist@hsphsun2.harvard.edu
[mailto:owner-statalist@hsphsun2.harvard.edu] Im Auftrag von Ronnie
Babigumira
Gesendet: Dienstag, 14. April 2009 09:36
An: statalist@hsphsun2.harvard.edu
Betreff: Re: st: AW: Quotes for scalar within local (was efficiently run
three loops (or do without them))

Thanks Martin.

That it is not a recommended strategy tells me I am doing something "wrong"
or that I need to be
careful. Might you know why it is not recommended.

Also, I am thinking that this revised code is closer to what Roy wrote only
I like to put this kind
of stuff out of the the main body of the code so that I can easily change
them (but I can live with
this anyway)

sysuse auto, clear
levelsof foreign, local(source)
foreach i of local source {
	levelsof rep78 if foreign == `i', local(rep)
		foreach j of local rep {
			g x = foreign == `i' & rep78 == `j'
			sum mpg if x
			drop x
			}
}

Martin Weiss wrote:
> <> 
> 
> If you wanted to make the -local- work here, you would have to delay
> evaluation with the "\" character. This is not a recommended strategy, but
> note the difference here:
> 
> *************
> sysuse auto, clear
> local x "foreign == `i' & rep78 == `j'"
> local y "foreign == \`i' & rep78 == \`j'"
> macro dir
> *************
> 
> 
> 
> HTH
> Martin
> 
> -----Ursprüngliche Nachricht-----
> Von: owner-statalist@hsphsun2.harvard.edu
> [mailto:owner-statalist@hsphsun2.harvard.edu] Im Auftrag von Ronnie
> Babigumira
> Gesendet: Dienstag, 14. April 2009 08:00
> An: statalist@hsphsun2.harvard.edu
> Betreff: st: Quotes for scalar within local (was efficiently run three
loops
> (or do without them))
> 
> Thanks
> Exploring your suggestion but wanting to put the checks in a macro rather
> than a variable, however,
> I am stuck (I have checked the archives but I cannot find a solution)
> 
> An illustration using the auto data
> 
> local x "foreign == `i' & rep78 == `j'"
> sysuse auto, clear
> levelsof foreign, local(source)
> foreach i of local source {
> 	levelsof rep78 if foreign == `i', local(rep)
> 		foreach j of local rep {
> 			sum mpg if `x'
> 			}
> }	
> 
> I have set the trace on and this is where it fails
> - sum mpg if `x'
> = sum mpg if foreign ==  & rep78 ==
> 
> Looks like the `i' and `j' disappear. I have fiddled around with different
> combinations of quotes
> but no luck.
> 
> Ronnie
> 
> 
> 
> Roy Wada wrote:
>>>
>>> gen check=1 if fup_pdt>`x' | fup_unit=`Y' | fup_qtycoll`x' &
fup_unit=`Y'
> & fup_qtycoll
>> 
>> where x, y, z are some conditions to be met. Then you would list them,
> i.e.
>>  
>> list fup_pdt fup_unit if check==1
>> 
>> And you'll know they aren't good at all.
>>  
>> _________________________________________________________________
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