I have the following problem:
in a research the use of medication in multiple patients is investigated. Every patient could list 3 different medicines in free text. Therefore, the data is shown for instance as follows:
patient medicine1 medicine2 medicine3
A valium diazepam zolax
B zolax valium asperin
C aspirin celecoxib oxynorm
How can I make a frequency-table that takes categories medicine 1, 2 and 3 together? I also want to be able to see that the combination on the first line (valium, diazepam and zolax) belongs to patient A, so my first question is: how can I take de frequencies of the 3 medicine coloms together, and secondly: how do I do this without losing the connection to the patient on the same line?
I have tried to do this with first recoding the free text into numerike data, but then I still can't figure it out..