Hello,

Thanks for your help. I think I should clarify. I'm not simply looking for a list of unique Patient ID#s. I already found that function in excel .

What I'm trying to do is more complicated.

This is a list of events. Each row represents a single event, which happens to be a cancer diagnosis. However, every patient has at least 2 events, some have more than 7.

I need a script that will evaluate each event, as a function of each patient, and return a list of patient IDs that only contains that subset of patients who had at least 2 events occurring within 6 months of each other.

Thank you again for helping out.