// Remove empty variables from dataset
foreach var of varlist * { // this does all vars or you could restrict
it to certain variables
capture confirm string `var' // need to handle string and number
differently
if !_rc==0 { // i.e. is not string
quietly summarize `var'
if `r(sum)' == 0 { // r(sum) is returned by summarize
drop `var'
display as txt "Dropping " as result "`var'"
}
}
else { // if a string
quietly count if `var' == ""
if `r(N)' == `c(N)' { // r(N) is returned by count
drop `var'
display as txt "Dropping " as result "`var'"
}
}
}
There are a couple of useful programming points in the above:
* foreach ... of varlist ... to loop through variables
* capture confirm string to test a variable's datatype
* using the return variables left by other commands
David Elliott MD, MSc
*
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* http://www.stata.com/support/faqs/res/findit.html
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