[Irene Solmone]

Carlo Lazzaro I tried, but the resulting dataset is all mixed up, there seems to be some kind of mistake - maybe because I am trying the code with three string vars instead of one.

[Irene Solmone]

Carlo Lazzaro I tried, but the resulting dataset is all mixed up, there seems to be some kind of mistake - maybe because I am trying the code with three string vars instead of one.

[Nick Cox]

The reason you can't manage is that you don't really have the same problem. You just have a relatively simple (*) problem in reshape long.

This seems to work with your data example. There will be a better name than whatever.

ds, has(type numeric)
rename (`r(varlist)') (whatever=)

reshape long whatever, i(Route Border Nationality) j(Date) string 

gen Mdate = monthly(Date, "MY")

format Mdate %tm

(*) In interviews of very rich people at some point the person often says "The first million (billion, trillion) dollars were the hardest". Sure.... In Stata the first 10 (100, 1000) reshapes are the hardest.

[Irene Solmone]

Thank you very much! I guess I have to practice....

[Nick Cox]

Only way to learn is to try it.