Program to recode all missing in SPSS to Stata missing

* Stata code
* Converts all values that equal missing such as -9999 to Stata missing values .

* Drops the program if it is already in the memory.
cap program drop recode_missing


* Defines a new program called recode_missing.
program define recode_missing

  local variable_changed = 0
  local variable_skipped_count = 0
  local variable_skipped


  * Loops through all variables identified by the first argument in the command.
  foreach v of varlist `1' {
   * Replaces the variable observations which match the second argument.
    capture replace `v'=. if `v'==`2'
   if _rc==0 local variable_changed = `variable_changed' + 1
   if _rc!=0 { 
      local variable_skipped_count = `variable_skipped_count' + 1
      local variable_skipped `variable_skipped' "`v'" 
   }
  }


  di "Recoded observations from `1' which equalled `2' into stata missing"
  di "# of variables changed: `variable_changed' "
  if `variable_skipped_count'!=0 {
 di "# of variables skipped: `variable_skipped_count' "
 di "skipped:  `variable_skipped'"
  }
end


* Example syntax
* . recode_missing * -9999
* This command will recode all variables that contain a -9999 into stata missing values ".".






***********************************************************
*          example of the command  in action              * 
use http://www.ats.ucla.edu/stat/stata/dae/logit.dta, clear
gen test="adsf"


* Does not make any logical sense to recode 0s as missing
recode_missing * 0


* Recoded observations from * which equaled 0 into stata missing
* # of variables changed: 4 
* # of variables skipped: 1 
* skipped:  test