st: Referencing Observations with Nested For Loops

["Alec N. Halaby" <halaby@fas.harvard.edu>]

Dear Stata Community,

I'm trying to write a straightforward program that is built around 
nested "forvalues" loops, and I've encountered difficulties in 
referencing specific observations using the counters. I've setup the for 
loops as follows, with the letters x and i used for the counters.:
forvalues x=1/4539 {
   if d04_05==1 & year==2004 {
   forvalues i=1/4539 {
         gen simscore`x'=games[x]-years[i]......

I would like to be able to retrieve data from two different observations 
in generating a new variable; for instance, observation 117 and 
observation 2,337 to generate games[117]-years[2337]. The reference and 
STATALIST material I've read has suggested that I use explicit 
subscripting to do this, and my instinct is to use square brackets to 
select an observation (i.e. games[117]-years[2,337]). However, when I 
insert the counters into the square brackets (games[x]-years[i], or in 
plain english "the games for observation x minus the years for 
observation i"), I get the error message that Stata is interpreting the 
contents of the brackets as weights. How would I use the counters to 
reference 2 different observations? I'm relatively new to STATA, so the 
answer may be as simple as a basic indexing method. Thanks in advance 
for any help you can provide!

Best,

Alec Halaby
     
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