匹配电子邮件的Python正则表达式

Question

My question is to write a function that, given an email address (a), returns (user, domain) corresponding to the user name and domain name. given bob@aus.space.com it should return (bob, aus.space.com).

The function should only match if it meets these following

A domain name must end with an alphabetic character. Alphabetic characters may be uppercase or lowercase. No whitespace characters are allowed.

Below is my current code and I am getting invalid syntax errors. Any insight on how to do this easier or cleaner would be much appreciated.

import re
def find_email (s):
  re_pattern = (r"(^[a-zA-Z0-9_.+-]+@[a-zA-Z0-9-]+\.[a-zA-Z0- 9-.]+$)")
  regular_expression_object = re.compile(re_pattern)
  match_object = regular_expression_object.match(s)
  if match_object != None:
    return (match_object.match(s).group('user'),match_object(s).group('domain'))
  else:
    raise ValueError

Answer 1

Seems this code would be what you are looking for:

import re
def find_email (s):
    re_pattern = (r"(?P<user>^[a-zA-Z][a-zA-Z0-9_.+-]+)@(?P<domain>[a-zA-Z0-9-._]+[a-zA-Z])$")
    regular_expression_object = re.compile(re_pattern)
    match_object = regular_expression_object.match(s)
    if match_object != None:
        return (match_object.group('user'), match_object.group('domain'))
    else:
        raise ValueError

[In]: find_email("user@email.domain.com")
[Out]: ('user', 'email.domain.com')

If you already made match of object you don't need to call "match" on it again - it already has groups.

Also its good practice to use some kind of regex-helping sites - there are multiple of them, such as regex101 for example.

Edit: Ok changed it up a little.

Since first character MUST be alphabetic, its [a-zA-Z] to check for it, followed by [a-zA-Z0-9_.+-] with + meaning 1 or more (can change it to * if you want 1-letter usernames) of alphanumeric characters plus those few special characters you gave in the original post.

After @ , [a-zA-Z0-9-._]+ means 1 or more of characters in this bracket, followed by [a-zA-Z] forcing the end of the line - $ to end with alphabetic character.

If you have still some mails that won't work - check some regex pages for this, with little tinkering it will work.