String variable in Do-file

[janno fe]

Noob question:

I need to use a string variable in the name of other variables. I thought of something like:

gen country="EU"
gen netexport_"country"=ex_"country" - im_"country"

It is just an example to illustrate my problem. A loop would be sub-optimal.

[Nick Cox]

Your first statement is legal. But if a new variable country contains "EU" in every observation it doesn't serve any purpose and bloats the dataset unnecessarily.

Your second statement is illegal, but I can't work out precisely what you want. Exports and imports surely always involve two countries....

As always, giving a concrete data example would help mightily. Please read and act on https://www.statalist.org/forums/help#stata

[janno fe]

I know that the second statement is illegal. What I want is that the entered string from the variable country is used in the second command.

[Nick Cox]

I can't add more without more explanation.

[William Lisowski]

Welcome to Statalist.

Perhaps what you want is not a "variable" at all, but rather a local macro.

local country EU
generate netexport_`country' = ex_`country' - im_`country'

and perhaps you ultimately want to loop over a list of countries

foreach country in EU US China {
    generate netexport_`country' = ex_`country' - im_`country'
}

and perhaps one of your variables contains country codes and you want to loop over each of the country codes in your dataset

levelsof countrycode, local(countries)
foreach country of local countries {
    generate netexport_`country' = ex_`country' - im_`country'
}

To learn more about these commands, see the output of

help local
help foreach
help levelsof

Lacking a sample of your data, none of the code above has been tested.