Validate password¶

A valid password must contain at least one lowercase letter, one uppercase letter, one digit and one special character, and be 7-20 characters long. Each rule is expressed as a separate lookahead:

reg = r"^(?=.*[a-z])(?=.*[A-Z])(?=.*\d)(?=.*[@$!%*#?&])[A-Za-z\d@$!#%*?&]{7,20}$"

Snippet to validate:

import re


def validate_pw(password):
    return re.search(re.compile(reg), password) is not None

See the runnable version with tests.