Tableau: custom grouping by string - tableau-api

Question

I’ve got data that looks like this:
Drug name:
Methylphenidate
Methylphenidate
Acetaminophen
Ritalin
Ritalin
Tylenol
Tylenol
I want tableau to treat “Ritalin” as “Methylphenidate”, and “Tylenol” as “Acetaminophen” for all purposes. I'm ideally hoping someone will point me to a menu or calculated field script where I can write out a long list of string substitutions. The full data set will have about 50 such changes to make.
For this example, I’m trying to count the number of times Methylphenidate/Ritalin is prescribed, and the number of times Acetaminophen/Tylenol is prescribed. Here, I want the output to be Ritalin = 4, and Tylenol = 3.
The only solution I can think of is to go into the data source, duplicate the "Drug name" column and run a "find and replace", but that's inelegant and would need to be repeated when data is added.
Thanks for the help.

Answer 1

If you are mapping multiple values to a single value (rolling them up), then use a Tableau group. The easiest way is to:
put Drug Name on the rows shelf
multi-select (shift-select) values that you want to combine
click the paperclip icon on the toolbar to group them together
right click on the resulting combined name and set a shorter alias of your choosing
The effect is to create a new group field based on the original Drug Name field that acts like the calculated field #Aron defined.
If instead you want to map each individual value to its own distinct label (say to display a meaningful name instead of a short cryptic code from the database), then you can create aliases instead of a group.

Answer 2

No problem. You can do this with a simple calculated field. Create a new calculated field and follow this logic
if [NDC Description] = 'Abilify' then 'user1791903'
elseif [NDC Description] = 'Actos' then 'user1791903'
elseif [NDC Description] = 'Actonel' then 'user1791903'
elseif [NDC Description] = 'Acyclovir' then 'Group2'
elseif [NDC Description] = 'Aciphex' then 'Group2'
else 'Unknown'
end
Basically, this will evaluate each record and depending on whether NDC Description is X or Y, it will output "user1791903" or "Group2" or "Unknown" if the record doesn't match any of the text you entered. Then, you can drag this calculated field to the shelf and it will display using this grouping, and you can then add aggregate functions and whatever else you need.

Answer 3

All these responses were very useful. The solution I ended up using:
I created a separate spreadsheet with a list of drug names and their generics. Then I ran a table join, adding it to the large dataset. This approach was valuable as it allowed me to easily add and edit drug definitions later on, and even add more metadata.
Thanks to everyone.