st: Value label gaps

[Jakob Petersen <jpeterb@essex.ac.uk>]

I would like to find variables with value label gaps and would 
appreciate some ideas.

-labelbook,problems- does detect variables with value label gaps, but 
includes variables with breaks in the consecutive order of values (e.g. 
1/2/3/4/98/99), where the higher numbers could represent expected 
non-valid codes.

-decode- could be used, but is very slow

sysuse auto,clear
la def origin 1 "",modify  // introduce value gap error in foreign
findname,vallab
foreach v of varlist `r(varlist)' {
tempvar vs
decode `v',gen(`vs')
distinct `v'
local nv=`r(ndistinct)'
distinct `vs'
local nvs=`r(ndistinct)'
if `nv'!=`nvs' {
if `nv'<100 {
fre `v'
}
else {
di "`v' has value label gaps and >=100 distinct values"
}
}
}

Many thanks in advance,
Jakob Petersen

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