Validating and Parsing Email Addresses - Hacker Rank Solution

A valid email address meets the following criteria:

• It's composed of a username, domain name, and extension assembled in this format: username@domain.extension
• The username starts with an English alphabetical character, and any subsequent characters consist of one or more of the following: alphanumeric characters, -,., and _.
• The domain and extension contain only English alphabetical characters.
• The extension is , , or  characters in length.

Given  pairs of names and email addresses as input, print each name and email address pair having a valid email address on a new line.

Hint: Try using Email.utils() to complete this challenge. For example, this code:

import email.utils
print email.utils.parseaddr('DOSHI <DOSHI@hackerrank.com>')
print email.utils.formataddr(('DOSHI', 'DOSHI@hackerrank.com'))

produces this output:

('DOSHI', 'DOSHI@hackerrank.com')
DOSHI <DOSHI@hackerrank.com>

Input Format

The first line contains a single integer, , denoting the number of email address.
Each line  of the  subsequent lines contains a name and an email address as two space-separated values following this format:

name <user@email.com>

Constraints

Output Format

Print the space-separated name and email address pairs containing valid email addresses only. Each pair must be printed on a new line in the following format:

name <user@email.com>

You must print each valid email address in the same order as it was received as input.

Sample Input

2  
DEXTER <dexter@hotmail.com>
VIRUS <virus!@variable.:p>

Sample Output

DEXTER <dexter@hotmail.com>

Explanation

dexter@hotmail.com is a valid email address, so we print the name and email address pair received as input on a new line.
virus!@variable.:p is not a valid email address because the username contains an exclamation point (!) and the extension contains a colon (:). As this email is not valid, we print nothing.

Validating and Parsing Email Addresses - Hacker Rank Solution

We can extract the input using email.utils.parseaddr(). Next, we use the following RegEx to validate the email:

^[a-zA-Z][\w\-\.]*@[A-Za-z]+\.[a-zA-Z]{1,3}$ 

Finally, we use email.utils.formataddr() to output the valid names and email addresses.

import re
from email.utils import *
for i in range(int(raw_input())):
    email = parseaddr(raw_input())
    # print email[1]
    # \w is equivalent to a-zA-Z_
    if bool(re.search(r'^[a-zA-Z][\w\-\.]*@[A-Za-z]+\.[a-zA-Z]{1,3}$', email[1])):
        print formataddr(email)