How to check that a variable exists

[Nicolas Orgeira]

Hi,

I would like to know whether a variable exists or not. I am currently using the following code:

foreach var of varlist q1 q2 q3 {
    capture confirm variable `var'_e
    if !_rc {
        display "`var'_e exists"
    }
    else {
        display "`var'_e does not exist
    }
}

However, with the code above, even if q1_e does not exist but q1_e_other does, it will display "q1_e exists" while I should be getting "q1_e does not exist". How can I change my code to display the correct message?

Thank you

[Aaron McMillan]

Hi there,

You'll just need to add the 'exact' option to the confirm command:

foreach var of varlist q1 q2 q3 {
    capture confirm variable `var'_e, exact
    if !_rc {
        display "`var'_e exists"
   }
   else {
      display "`var'_e does not exist
   }
}

Alternatively, you could 'set varabbrev off' entirely if you wish. 'novarabbrev' can also be handy to know of in some other situations.