PYTHON
Validating IPv4 Addresses with Regular Expressions in Python
Learn to accurately validate IPv4 address formats using a robust regular expression in Python, ensuring correct network address inputs in your applications.
import re
def is_valid_ipv4(ip_address):
# Regex for an IPv4 address, ensuring each octet is 0-255
ipv4_regex = r"^((25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$"
return re.match(ipv4_regex, ip_address) is not None
print(is_valid_ipv4("192.168.1.1")) # True
print(is_valid_ipv4("10.0.0.255")) # True
print(is_valid_ipv4("256.0.0.1")) # False (256 is invalid)
print(is_valid_ipv4("192.168.1")) # False (incomplete)
How it works: This Python function `is_valid_ipv4` employs a precise regular expression to validate if a string is a correctly formatted IPv4 address. The regex ensures that each of the four octets is a number between 0 and 255, and that they are separated by dots, making it suitable for input validation.