1517-FindUsersWithValidEMails.py

# 1517. Find Users With Valid E-Mails
# Table: Users
# +---------------+---------+
# | Column Name   | Type    |
# +---------------+---------+
# | user_id       | int     |
# | name          | varchar |
# | mail          | varchar |
# +---------------+---------+
# user_id is the primary key (column with unique values) for this table.
# This table contains information of the users signed up in a website. Some e-mails are invalid.
 
# Write a solution to find the users who have valid emails.
# A valid e-mail has a prefix name and a domain where:
# The prefix name is a string that may contain letters (upper or lower case), digits, underscore '_', period '.', and/or dash '-'. The prefix name must start with a letter.
# The domain is '@leetcode.com'.
# Return the result table in any order.
# The result format is in the following example.

# Example 1:
# Input: 
# Users table:
# +---------+-----------+-------------------------+
# | user_id | name      | mail                    |
# +---------+-----------+-------------------------+
# | 1       | Winston   | winston@leetcode.com    |
# | 2       | Jonathan  | jonathanisgreat         |
# | 3       | Annabelle | bella-@leetcode.com     |
# | 4       | Sally     | sally.come@leetcode.com |
# | 5       | Marwan    | quarz#2020@leetcode.com |
# | 6       | David     | david69@gmail.com       |
# | 7       | Shapiro   | .shapo@leetcode.com     |
# +---------+-----------+-------------------------+
# Output: 
# +---------+-----------+-------------------------+
# | user_id | name      | mail                    |
# +---------+-----------+-------------------------+
# | 1       | Winston   | winston@leetcode.com    |
# | 3       | Annabelle | bella-@leetcode.com     |
# | 4       | Sally     | sally.come@leetcode.com |
# +---------+-----------+-------------------------+
# Explanation: 
# The mail of user 2 does not have a domain.
# The mail of user 5 has the # sign which is not allowed.
# The mail of user 6 does not have the leetcode domain.
# The mail of user 7 starts with a period.

import pandas as pd

def valid_emails(users: pd.DataFrame) -> pd.DataFrame:
    # ^[a-zA-Z] 前缀必须字母开头 
    # 字符串包含 [a-zA-Z0-9_.-]* 星号代表包含以上中括号内的字符和特殊含义字符的任意字符 
    # 以 @leetcode.com 结尾 @leetcode\.com$ 在正则表达式中.为特殊含义字符 需要转义\
    users = users[users["mail"].str.match(r"^[a-zA-Z][a-zA-Z0-9_.-]*@leetcode\.com$")]
    return users

if __name__ == "__main__":
    data = [[1, 'Winston', 'winston@leetcode.com'], [2, 'Jonathan', 'jonathanisgreat'], [3, 'Annabelle', 'bella-@leetcode.com'], [4, 'Sally', 'sally.come@leetcode.com'], [5, 'Marwan', 'quarz#2020@leetcode.com'], [6, 'David', 'david69@gmail.com'], [7, 'Shapiro', '.shapo@leetcode.com']]
    users = pd.DataFrame(data, columns=['user_id', 'name', 'mail']).astype({'user_id':'int64', 'name':'object', 'mail':'object'})
    
    print(valid_emails(users))