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 Emailregex = r'\b[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Z|a-z]{2,7}\b'# Define a function for# for validating an Emaildef 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 Codeif __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) |
Valid Email Valid Email Invalid Email
Time complexity : O(n), where n is length of string.
Auxiliary Space : O(1)
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 Emaildef 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 Codeif __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) |
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, EmailNotValidErrordef 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 rea = 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
Method 5: Validate Emails using an Email Verification API
Email verification services tell you whether an email address is valid syntax, but they also tell you if the address is real and can accept emails, which is super useful and goes beyond just basic validation. The services are usually pretty cheap (like $0.004 USD per email checked). For this example we’ll be using Kickbox, but there are many such services available.
Python3
# Full docs on GitHub - https://github.com/kickboxio/kickbox-pythonimport kickboxdef is_email_address_valid(email, api_key): # Initialize Kickbox client with your API key. client = kickbox.Client(api_key) kbx = client.kickbox() # Send the email for verification. response = kbx.verify(email) # check the response code if you like # assert response.code == 200, "kickbox api bad response code" # We can exclude emails that are undeliverable return response.body['result'] != "undeliverable" |
You can also use the results to check if an email address is disposable ( response.body[‘disposable’] ), or from a free provider – like if you wanted to only accept business email addresses ( response.body[‘free’] ).
