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RE: st: Adding variables with common prefix


From   "Nick Cox" <n.j.cox@durham.ac.uk>
To   <statalist@hsphsun2.harvard.edu>
Subject   RE: st: Adding variables with common prefix
Date   Tue, 30 May 2006 13:50:30 +0100

A detail worth emphasising is that the original
code used a scalar only at the very last step. 
This cannot of course reclaim any precision lost
by using locals previously. Often this won't 
matter in practice, but not always. 

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

n j cox
 
> Look again at the help for -foreach-.
> 
> foreach v of var var* {
> 
> That is, you must specify that var* is a varlist.
> 
> I would also use a scalar here.
> 
> scalar mysum = 0
> foreach v of var var* {
> 	scalar mysum = mysum + `v'[1]
> }

R.E. De Hoyos
 
> I have a large list of variables with a common prefix, say 
> -var- (var1, 
> var2, var3...). I want to generate a scalar with the sum of these 
> variable's first observation. I tried the following loop, but 
> for some 
> reason that I can't see it is not working, it returns an 
> invalid syntax 
> error message:
> 
> local sum = 0
> foreach v of var* {
> local sum = `sum' + `v'[1]
> }
> scalar answer = `sum'
> 
> What is wrong with this code? Is there an alternative way of 
> adding up 
> variables with a common prefix?

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