How to count strings across variables*

[Simwinga Simwinga]

Hello,
How can I count string values (Topic_1 through to Topic_4) across multiple variables ? I want the count to be in the variable _NTopics.

[Simwinga Simwinga]

I tried to follow the example on Stata | FAQ: Counting distinct strings across a set of variables but to no avail. I am getting this

response in the attachment.

[William Lisowski]

Welcome to Statalist.

You have accidentally posted your topic in Statalist's Mata Forum, which is used for discussions of Stata's Mata language, which is different than Stata's command language, and different than Stata's matrix commands. Your question will see a more appropriate and much larger audience if you post it in Statalist's General Forum.

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