Hi!
I need help to create the values in a variable automatically from two other variables.

My data consists of a number of distance variables called dist_1, dist_2, dist_3 and etc which is a code for the individuals postalcode, it also consists of a variable called skolepostnr, which indicates which postalcode the school an individual attends to and postnummer, which indicates the postalcode an individual lives in. I have created a variable called dist_skole_hjem, which should be used to measure the distance between an individuals home and school, fx the individual have skolepostnr=3 and postnummer=2, so the dist_skole_hjem in this case should equal 55.


Postnummer dist_1 dist_2 dist_3 ... skolepostnr dist_skole_hjem
1 20,5 40,7 90 1
2 45 120 55 3
... ... ... ... ...
Since there are a lot of observations in my dataset, I would like to know if there is some way that I could generate this automatically without using the replace command like this:

replace dist_skole_hjem = 55 if postnummer == 2 & skolepostnr =="3"

So if there is some way that I could get stata to automatically fill out the dist_skole_hjem variable with the information from my dist_1, dist_2, dist_3 etc using the variables postnummer and skolepostnr and obtain the same as if I used the replace command?

Hope you can help me!