foreach with multiple varlists

[Corinna Bordewieck]

Hi Statalist members,

I am comparing data on responses to thirty test questions ("variable") to the correct answers to those questions ("a_variable"). I want to generate a new variable that tells me whether the response is correct, incorrect, or missing ("r_variable").

In other words, I want to run this code for thirty variables (one varlist) against thirty response variables (another varlist):

gen r_variable=1 if variable==a_variable
replace r_variable=0 if variable!=a_variable
replace r_variable=. if variable>;=99

(My codes for "missing" or "incomplete" are values 99 and higher, so I have no missing values in my original variables.)

I searched previous posts but couldn't figure out how to apply responses to my data and variables.

I am using Stata 11.2.

Thank you very much!

Best,
Corinna

[Sebastian Geiger]

I'm not sure if I understand you correctly, but my first guess is to put your code in a -foreach var in ... - loop. Where the ... need to be replaced with the names of your variables (without the stubs r_ etc.). Then, you can replace variable with `var' in your code.

[Roger Chu]

Hello Corinna,

Welcome to Statalist! For future posts, its helpful if you present your code within CODE delimiters -- it makes it easier to read. See http://www.statalist.org/forums/help#stata for more info.

Try this code:

foreach var of varlist VARIABLES { //VARIABLES = the varlist of your responses
    gen r_`var' = `var'==a_`var'
    replace r_`var' = . if `var'>=99
}

In the above code, I assume that you have consistency in naming of variables. That is, if your response variable is named "question1", then your correct answer variable is named "a_question1".