Python, Regex, extract grouped emails within curly brackets

I’m trying to extract multiple Emails from string. I’m using this regex:

re.findall(r'[w.-]+@[w.-]+(?:.[w]+)+', text)

It works fine, but sometimes in text Email names with the same domain are grouped in curly brackets:

{annie,bonnie}@gmail.com

So my question is how properly to parse it and extract as separate emails:
[e-mail], [e-mail]?

I’ve tried to modify regex to take into account brackets and comma, following with simple function, but in that case I get a lot of garbage from string.

Any help appreciated.

Answer

You can use

(?:{([^{}]*)}|bw[w.-]*)(@[w.-]+.w+)

See the regex demo. Details:

• (?:{([^{}]*)}|bw[w.-]*) – a non-capturing group matching:
• {([^{}]*)} – a {, then Group 1 capturing any zero or more chars other than { and } and then a }
• | – or
• bw[w.-]* – a word boundary (it will make matching more efficient), a word char, and then zero or more word, dot or hyphen chars
• (@[w.-]+.w+) – Group 2: a @, one or more word, dot or hyphen chars, then a . and one or more word chars.

See a Python demo:

import re
text = "Emails like {annie,bonnie}@gmail.com, [e-mail], then a [e-mail]."
emails = []
rx_email = re.compile( r'(?:{([^{}]*)}|bw[w.-]*)(@[w.-]+.w+)' )
for m in rx_email.finditer(text):
    if m.group(1):
        for email in m.group(1).split(','):
            emails.append(f'{email}{m.group(2)}')
    else:
        emails.append(m.group())
print(emails)
# => ['[e-mail]', '[e-mail]', '[e-mail]', '[e-mail]']

The logic is

• Get the emails with {...} in front of @ while capturing the contents inside the braces into Group 1 and the @... into Group 2
• Check if Group 1 was matched, and if yes, split the contents with a comma and build the resulting matches by concatenating the comma-separating user names with the domain part
• If Group 1 did not match, just append the match value to the resulting list.