A while ago I needed to extract e-mail addresses from a CSV file, but the addresses weren’t isolated in a specific field. I wrote a short Python script to get triggered by Automator. Now I can drop a CSV file on to the Automator “app” and it will create a new column in the file with just an e-mail address.
The script is crude, but works well enough for me. It only finds the first address in a row. The regular expression is simple, too, so it will likely miss a few or grab false positives. It also overwrites the source file, which would not be good for a more serious workflow, but it is fine for my current purpose: