Hi,

I have something that is confusing me. I have a dataset and want to merge it with another, but before I can do that I have to drop all entries which are the same personID, same varA, but different varB.

I want to table 1 to become table 2.

Is there a way to do this?

I have been trying to use this explanation, https://www.stata.com/support/faqs/d...-observations/ but have not been able to get it to work yet.

Thanks.

Table 1
PersonID varA varB
1 a ab
1 a ab
2 c cd
3 a ab
3 a ac
4 z zy
4 z zy
5 z zy
5 z zx
Table 2
PersonID varA varB
1 a ab
1 a ab
2 c cd
4 z zy
4 z zy