Regular Expressions Basics

import re

text = "Contact us at support@email.com or visit https://example.com"

# re.search() — find first match
match = re.search(r'\w+@\w+\.\w+', text)
if match:
    print(f"Email found: {match.group()}")

# re.findall() — find all matches
emails = re.findall(r'[\w.]+@[\w.]+', text)
print(f"All emails: {emails}")

# re.sub() — replace
cleaned = re.sub(r'\d+', 'X', "Order 123 shipped on 2024-01-15")
print(cleaned)

# Common patterns
phone = "My number is 9876543210"
print(re.findall(r'\d{10}', phone))  # ['9876543210']

# Validate email
def is_valid_email(email):
    pattern = r'^[\w.]+@[\w]+\.[a-zA-Z]{2,}$'
    return bool(re.match(pattern, email))

print(is_valid_email("alice@gmail.com"))   # True
print(is_valid_email("invalid@"))          # False

# Extract data
log = "2024-01-15 ERROR Server crashed"
parts = re.match(r'(\d{4}-\d{2}-\d{2}) (\w+) (.*)', log)
if parts:
    print(f"Date: {parts.group(1)}")
    print(f"Level: {parts.group(2)}")
    print(f"Message: {parts.group(3)}")