If you type -di `"`models'"'- before the beginning of the loop you can
see the content of the local:
"_Idrug*"" ""_Idrug* age"
The local contains three strings:
1. "_Idrug*"
2. " "
3. "_Idrug* age"
So the second model that you try to estimate is:
stcox , nocons
and this is not allowed.
Basically you want to separate models by surrounding them by quotes, so
your list containing all models must contain quotes. That list is
itself a string. In Stata (and many other languages) strings are
themselves surrounded by quotes, so you must tell Stata which quote is
part of the string (delimitating models) and which quote means end of
string. The way to do that is to suround that string with compound
quotes `" and "'. Anyting between `" and "' is part of the string
including any ". This way Stata can discern between the beginning and
end of the string and the " that is part of the string. You can read
more about this in -help quotes-.
A working example is below. Notice the way compound quotes are used to
indicate that " is part of the string:
*------------- 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"
di `"`models'"'
foreach m in `models' {
stcox `m' `options'
foreach var in `m' {
testparm `var'
}
}
*-------------- end example ----------------
Hope this helps,
Maarten
Ps. be careful with using all captial letters when posting to mailing
lists. This is generally seen as the equivalent of shouting and is very
rarely appropriate.
--- K Jensen <k.x.jensen@googlemail.com> wrote:
Thanks for the -tuples- suggestion, Maarten. It looks like a useful
command in other contexts, but I don't want to run all possible
combinations of variables.
So, the mystery remains. Can ANYONE out there explain why the code
marked "A" below works, but the code "B" gets the error message
"option nolog not allowed" when it runs model2? Please!?
Yours desperately
Karin
*------------- begin A ---------------
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'
}
}
*-------------- end A ----------------
*------------- begin B ---------------
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'
}
}
*-------------- end B ----------------
On 16/06/07, Maarten buis <maartenbuis@yahoo.co.uk> wrote:
what about Nick's -tuples- command? See: -ssc desc tuples-
Hope this helps,
Maarten
--- K Jensen <k.x.jensen@googlemail.com> wrote:
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:
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
