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Re: st: Re: foreach program
Dear Michael,
If there is a faster way to do what I'm doing, then I'd love to know
it, as the code I use takes me a few days to execute because of the
computer I'm using and the size of the Census longform survey.
Here's a description of what I'm doing. I am calculating
incarceration rates by demographic cell, which is defined at the
United States state-age-race-sex-year level. I have data for 1980,
1990 and 2000. In 1980, the "group quarter" variable was definite
differently than how it was defined in 1990 and 2000, so I've been
running two do files - one for 1980 and one for 1990/2000, but they
are essentially identical.
I have 9 different age cohorts. I only reported the code for one of
them, since they are all identical calculations. The age cohorts are:
1. 15-19 year olds
2. 20-24 year olds
3. 25-29 year olds
4. 30-34 year olds
5. 35-39 year olds
6. 40-44 year olds
7. 45-54 year olds
8. 55-64 year olds
9. 65+ year olds
I have 51 states (50 US states plus District of Columbia).
I have two races (black and white), two sex values, and three census
years (1980, 1990 and 2000). My understanding was that to create so
many separate incarceration rates and levels, I would need to
reproduce the same code for each demographic cell. So I've been
using -foreach- to do it. Do you disagree, though, that this is not
the most efficient method?
sc
On Sep 8, 2006, at 12:02 PM, Michael Blasnik wrote:
I've been reading this thread and don't understand why you need to
loop at all or generate the grouping variable. Wouldn't it make
more sense to use a collapse and a reshape?
keep if inrange(age,15,19)
gen byte groupqtrs=(gqtyped==200)
collapse (sum) perwt, by(fip race sex groupqtrs)
reshape wide perwt, i(fip race sex) j(groupqtrs)
gen totpersons=perwt0+perwt1
gen ir=perwt1/totpersons
This approach seems easier and faster and gives you a dataset of
results directly.
You could take the results and merge them back into the main
dataset if you want, but I don't even think that is necessary.
Michael Blasnik
[email protected]
----- Original Message ----- From: "Scott Cunningham"
<[email protected]>
To: <[email protected]>
Sent: Friday, September 08, 2006 10:47 AM
Subject: st: foreach program
<snip>
egen group=group(fip race sex)
su group, meanonly
foreach i of num 1/`r(max)' {
gen i=perwt if age>=15 & age<=19 & group==`i' & gqtyped==200
gen p=perwt if age>=15 & age<=19 & group==`i'
egen itot=sum(i)
egen ptot=sum(p)
replace ir_level=itot if age==15 & group==`i'
replace pop_level=ptot if age==15 & group==`i' replace ir=itot/
ptot if age==15 & group==`i'
drop i p itot ptot
}
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