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RE: st: how do i increment a counter


From   "Nick Cox" <n.j.cox@durham.ac.uk>
To   <statalist@hsphsun2.harvard.edu>
Subject   RE: st: how do i increment a counter
Date   Wed, 31 Aug 2005 22:49:51 +0100

Meaning, 

gen age_category = cond(age <= 50, 1, 
                   cond(age <= 75, 2, 
                   cond(age <= 90, 3, 4)))
 
tabstat exposure_time, s(sum) by(age_category)

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

> -----Original Message-----
> From: owner-statalist@hsphsun2.harvard.edu
> [mailto:owner-statalist@hsphsun2.harvard.edu]On Behalf Of Nick Cox
> Sent: 31 August 2005 22:33
> To: statalist@hsphsun2.harvard.edu
> Subject: RE: st: how do i increment a counter
> 
> 
> As others have advised, no loops are needed 
> for a problem like this. I guess at 
> 
> gen age_category = cond(age <= 50, 1, 
>                    cond(age <= 75, 2, 
>                    cond(age <= 90, 3, 4)))
> 
> tabstat exposure_time, s(sum) by(exposure_time)
> 
> Nick 
> n.j.cox@durham.ac.uk 
> 
> aine dooley
>  
> > What I am actually trying to do is loop through a list of 
> > 6500 patients. 
> > Each patient has an exposure_time i.e. the period of time in 
> > days during 
> > which they are at risk for a fracture. For each age category 
> > (see below), I 
> > want to add up a cumulative time at risk. So for ages 51-75, 
> > I want to come 
> > out with a number that contains the total exposure_time for 
> > all patient in that age category.
> > 
> > I think numlist apparently only allows 1600 observations 
> > which is somehow 
> > incremented by using numlist, max('totobs`) though I haven't 
> > figured out the 
> > syntax.
> > 
> > I'm sure there is a more elegant way to do this, however ...
> > 
> > local age1_sum=0
> > local age2_sum=0
> > local age3_sum=0
> > local age4_sum=0
> > local totobs = _N
> > 
> > foreach obs of numlist 1/`totobs' {
> >    if age[`obs']<=50 {
> >       local age1_sum = `age1_sum' + exposure_time[`obs']
> >    }
> >    else if age[`obs'] >50 & age[`obs'] <= 75 {
> > 	      local age2_sum = `age2_sum' + exposure_time[`obs']
> >    }
> >    else if age[`obs'] >75 & age[`obs'] <= 90 {
> > 	      local age3_sum = `age3_sum' + exposure_time[`obs']
> >    }
> >    else local age4_sum = `age4_sum' + exposure_time[`obs']
> > }
> > 
> > 
> 
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