Extract email sub-strings from large document

Question

I have a very large .txt file with hundreds of thousands of email addresses scattered throughout. They all take the format:

......
         


        

Answer 1

import re
rgx = r'(?:\.?)([\w\-_+#~!$&\'\.]+(?

Please don't hate me for having a go at this infamous regex. The regex works for a decent portion of email addresses shown below. I mostly used this as my basis for the valid chars in an email address.

Feel free to play around with it here

I also made a variation where the regex captures emails like name at example.com

(?:\.?)([\w\-_+#~!$&\'\.]+(?