RE: st: RE: Removing variables with no observation from datasets

[adiallo5@worldbank.org]

Hi Nick

Thanks a lot.
The command ds3 works perfectly.

Best.




                                                                                                                                                
                      "Nick Cox"                                                                                                                
                      <n.j.cox@durham.ac.uk>            To:      <Statalist@Hsphsun2.Harvard.Edu>                                               
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                      owner-statalist@hsphsun2.         Subject: RE: st: RE: Removing variables with no observation from datasets               
                      harvard.edu                                                                                                               
                                                                                                                                                
                                                                                                                                                
                      01/16/2003 10:42 AM                                                                                                       
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adiallo5@worldbank.org
>
> DHS are the Macro-International databases on Demographic
> and Health Surveys.
> Many variables in these datasets contains missings
> observations and are
> labelled with NA: I mean:
> e.g:
> - v224 "Child receives juice, NA"
> -tab v224
> . no observation
>
> I want to know how to drop these variables.

If a variable label ending in "NA" means that
the variable is of no use, then you
can use -ds3- from SSC to drop such variables.

ds3, has(varl *NA)
drop `r(varlist)'

Alternatively, here is the route from first
principles.

foreach v of var * {
             local label : variable label `v'
             if substr(`"`label'"',-2,2) == "NA" {
                         drop `v'
             }
}

On the other hand, if the diagnostic is
just no non-missing values, then use
-dropmiss- as previously mentioned, or

foreach v of var * {
             capture assert missing(`v')
             if _rc == 0 {
                         drop `v'
             }
}

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