st: extract string portion

[thomas bourveau <thomas.bourveau@gmail.com>]

Dear Statalist,

I am working on a dataset where I need to extract an identifier for
the parent company of my observations. Here are two examples:

OnlineChoice.com, Inc. (Exelon Corporation (NYSE:EXC))
Peppers & Rogers Group (TeleTech Holdings Inc. (NasdaqGS:TTEC))

As you can see the dataset provides the name of the company, its stock
exchange and its identifier (the Ticker) in the same row.

I'm interested in retrieving the Ticker (EXC and TTEC in the
abovementioned examples).

I have read some things on using the regex command to extract figures
from a string expression, but I did not found how to select only a
string portion of it.

If anyone has an idea, I will be grateful and try to implement it.

Thanks
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