Check if email address valid or not in Python

Given a string, write a Python program to check if the string is a valid email address or not. An email is a string (a subset of ASCII characters) separated into two parts by @ symbol, a “personal_info” and a domain, that is personal_info@domain.

Examples:

Input:  ankitrai326@gmail.com
Output: Valid Email

Input: my.ownsite@ourearth.org
Output: Valid Email

Input: ankitrai326.com
Output: Invalid Email 

Method 1: Check for a valid email address using regular expression

This method either returns None (if the pattern doesn’t match) or re.MatchObject contains information about the matching part of the string. This method stops after the first match, so this is best suited for testing a regular expression more than extracting data. 

Python3

import re

# Make a regular expression
# for validating an Email
regex = r'\b[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Z|a-z]{2,7}\b'

# Define a function for
# for validating an Email
def check(email):

    # pass the regular expression
    # and the string into the fullmatch() method
    if(re.fullmatch(regex, email)):
        print("Valid Email")

    else:
        print("Invalid Email")

# Driver Code
if __name__ == '__main__':

    # Enter the email
    email = "ankitrai326@gmail.com"

    # calling run function
    check(email)

    email = "my.ownsite@our-earth.org"
    check(email)

    email = "ankitrai326.com"
    check(email)

Output

Valid Email
Valid Email
Invalid Email

Method 2: Validate Email Address with Python using re.match

The re.match() searches only from the beginning of the string and returns the match object if found. But if a match of substring is found somewhere in the middle of the string, it returns none. 

Python3

import re

# Define a function for
# for validating an Email
def check(s):
    pat = r'\b[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Z|a-z]{2,7}\b'
    if re.match(pat,s):
        print("Valid Email")
    else:
        print("Invalid Email")

# Driver Code
if __name__ == '__main__':

    # Enter the email
    email = "ankitrai326@gmail.com"

    # calling run function
    check(email)

    email = "my.ownsite@our-earth.org"
    check(email)

    email = "ankitrai326.com"
    check(email)

Output

Valid Email
Valid Email
Invalid Email

Method 3: Test if the email address is valid or not in Python using email_validator

This library validates that a string is of the form name@example.com. This is the sort of validation you would want for an email-based login form on a website. Gives friendly error messages when validation fails.

Python3

from email_validator import validate_email, EmailNotValidError

def check(email):
    try:
      # validate and get info
        v = validate_email(email)
        # replace with normalized form
        email = v["email"]
        print("True")
    except EmailNotValidError as e:
        # email is not valid, exception message is human-readable
        print(str(e))

check("my.ownsite@our-earth.org")

check("ankitrai326.com")

Output:

True
The email address is not valid. It must have exactly one @-sign.

Method 4: Validate Emails From a Text File Using Python

in this method, we will use re.search from regex to validate our from a text file, We can filter out many email from a text file.

Python3

import re
a = open("a.txt", "r")
# c=a.readlines()
b = a.read()
c = b.split("\n")
for d in c:
    obj = re.search(r'[\w.]+\@[\w.]+', d)
    if obj:
        print("Valid Email")
    else:
        print("Invalid Email")

Output:

Valid Email
Invalid Email