给定一个以电子邮件地址结尾的文本字符串，我如何屏蔽：
- 除电子邮件ID的第一个字母外的所有字母
- 域名的一部分
样本输入：
"The quick brown fox jumps over the lazy dog. china@youwan.com"
预期结果：
"The quick brown fox jumps over the lazy dog. cxxxx@xxxxx.com"
- 识别数据中的电子邮件地址
>>> input_text = "The quick brown fox jumps over the lazy dog. china@youwan.com"
>>> body, email_id = input_text.rsplit(' ', 1)
>>> email_id
'china@youwan.com'
- 将电子邮件地址替换为
x
>>> import re
>>> email_split = re.split('@|.', email_id)
>>> email_split
['china','youwan','com']
>>> username, domain_front, *domain_back_list = email_split
>>> username_masked = username[0]+'x'*(len(username)-1)
>>> domain_front_masked = 'x'*len(domain_front)
>>> domain_back = '.'.join(domain_back_list)
>>> email_masked = '{}@{}.{}'.format(username_masked, domain_front_masked, domain_back)
>>> email_masked
'cxxxx@xxxxx.com'
- 将屏蔽的电子邮件地址与原始文本字符串连接起来：
>>> result = '{} {}'.format(body, email_masked)