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Re: st: Strange problem with stcox inside a loop


From   "K Jensen" <k.x.jensen@googlemail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: Strange problem with stcox inside a loop
Date   Sat, 16 Jun 2007 12:54:19 +0100

Thanks for replying, Maarten.

Unfortunately, the solution you posted runs  _Idrug* and age as
separate models, which wasn't what I intended, and was why I used the
double quotes as I did.

The results on the analogous code for regress on the auto dataset that
I posted before do work, and show what I was trying to do.

With best wishes and thanks
Karin

On 16/06/07, Maarten buis wrote:
--- K Jensen <k.x.jensen@googlemail.com> wrote:
I am trying to use some foreach loops to run various stcox models
and to use testparm on them.  I have a problem on the second run
on each loop.  What I'm doing is more complex, but the following
code on the system "cancer" dataset causes the same problem:

sysuse cancer
stset studytime, fail(died)
xi i.drug
local model1 ""_Idrug*""
local model2 ""_Idrug* age""
local models "`model1'" "`model2'"
local options ", nolog"
foreach m in `models' {
  stcox `m' `options'
  foreach var in `m' {
      testparm `var'
  }
}
This works fine for model1, which produces results as expected,
but on model2 it generates the error message:
"option nolog not allowed"
The problem has to do with the way you use double quotes. It's use
is explained in -help quotes-. An example that works is shown
below:

*------------- begin example ---------------
sysuse cancer, clear
stset studytime, fail(died)
xi i.drug
local model1 "_Idrug*"
local model2 "_Idrug* age"
local models `"`model1' `model2'"'
local options ", nolog"

foreach m in `models' {
 stcox `m' `options'
 foreach var in `m' {
     testparm `var'
 }
}
*-------------- end example ----------------

Hope this helps,
Maarten

I don't think it's a function of the way I have written the loop,
as an analogous loop with the regress command works perfectly
well:
sysuse auto
xi i.rep78
local model1 ""_Irep78*""
local model2 ""_Irep78* weight""
local models "`model1'" "`model2'"
local options ", noheader"
foreach m in `models' {
  regress price `m' `options'
  foreach var in `m' {
      testparm `var'
  }
}

Can anybody explain why this is happening?

Thankyou
Karin
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