Re: repost: -cond()- function

[Michel Camus <mcamus@videotron.ca>]

I experience the same "problem" as you do, Paul.
I believe it has to do with "binary logic". The logical condition 
("chol") always evaluates to 0 or 1, and nothing else,  it  never 
evaluates to "9" even if the original variable does have "9" as one 
value. The same happens even if your missing values in "chol" were 
already coded as "." 
See http://www.stata.com/support/faqs/data/values.html  by W. Gould on 
"Logical expressions and missing values". 
The way to have missing values is tocondition your expression as follows 
:    
           .gen cholcat = cond(chol,0,1) if chol != 9
Then you would still have to replace the missing (".") by "9" however if 
that is what you want.

Michel Camus
===============================
VISINTAINER PAUL wrote:


> I am reposting this message:
>  
> I have an integer variable that I would like to collapse into a dichotomous variable. Using the following statement:
>
>      .gen cholcat = cond(chol,0,1,9)
>
> produces the same output as:
>
>     .gen cholcat = cond(chol,0,1)
>
> The first statement continues to recode "missings" as 1, not 9.  In order to capture the missings appropriately, I have to follow each -cond()- statement with a -replace- command.
>
>
> Am I using the -cond()- function appropriately?
>
> Thanks,
>
> paul visintainer
>
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>
>  
--

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Michel Camus, Ph.D.

Épidémiologue, Div. Biostatistique et épidémiologie, DGSESC, Santé Canada

Epidemiologist, Biostatistics and Epidemiology Div., HECSB, Health Canada

Courriel / e-mail : mcamus@videotron.ca <mailto:mcamus@videotron.ca>

Téléphone / phone     :    (514) 850-0157

Télécopieur / fax        :    (514) 850-0836

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*
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