Hello,

I am trying to figure out how to create a dummy variable for the first duplicates of the year and the country. My dataset is about civil conflict events that occur in a certain year (styr) in a certain country (ccode) and it looks like this. There are many more variables, but I don't think I need them for this. (Although I am not sure as I am not very good at working with stata.. So please let me know if you need any more info)

I have created the dup variable by using the following command: duplicates tag ccode styr, gen(dup).
I saw this in another forum and it does show how many duplicates there are per styr but now I don't know how to proceed. I've looked at many other forums but haven't found one that really answers my question.

So, I want to create a dummy that gives value 1 only for the first event per country / year 'match'. So in the picture I uploaded this would be for observation 1, 3, 4, 7, 16, 18, 19, 20, etc.


Array

I hope you can help as I have been stuck on this for quite a while now. Thanks!