使用 Python 正则表达式匹配字母数字单词、提及或电子邮件

Question

I've already read this and this and this and lots of others. They don't answer to my problem.

I'd like to filter a string that may contain emails or strings starting by "@" (like emails but without the text before the "@"). I've tested many ones but one of the simplest that begins to get close is:

import re
re.split(r'(@)', "test @aa test2 @bb @cc t-es @dd-@ee, test@again")
Out[40]: 
['test ', '@', 'aa test2 ', '@', 'bb ', '@', 'cc t-es ', '@', 'dd-', '@', 'ee, test', '@', 'again']

I'm looking for the right regexp that could give me:

['test ', '@aa', 'test2 ', '@bb ', '@cc', 't-es ', '@dd-', '@ee', 'test@again']

Answer 1

Why try to split when you can go "yo regex, give me all that matches":

test = "test @aa test2 @bb @cc t-es @dd-@ee, test@again"


import re

print(
    re.findall("[^\s@]*?@?[^@]* |[^@]*@[^\s@]*", test)
)
# ['test ', '@aa test2 ', '@bb ', '@cc t-es ', '@dd-', '@ee, ', 'test@again']

I tried but I couldn't make the regex any smaller, but at least it works and who expects regex to be small anyway

---

As per the OP's new requirements(or corrected requirements)

[^\s@]*?@?[^\s@]* |[^@]*@[^\s@]* 

Answer 2

My own solution based on different email parsing + simple " @[:alphanum:]+ " parsing is:

USERNAME_OR_EMAIL_REGEX = re.compile(
    r"@[a-zA-Z0-9-]+"  # simple username
    r"|"
    r"[a-zA-Z0-9.!#$%&'*+/=?^_`{|}~-]+"  # email 
    r"@"  # following: domain name:
    r"[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?"
    r"(?:\.[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?)")