Question

Using a regex in Python, how can I verify that a user’s password is:

• At least 8 characters
• Must be restricted to, though does not specifically require any of:
  • uppercase letters: A-Z
  • lowercase letters: a-z
  • numbers: 0-9
  • any of the special characters: @#$%^&+=

Note, all the letter/number/special chars are optional. I only want to verify that the password is at least 8 chars in length and is restricted to a letter/number/special char. It’s up to the user to pick a stronger / weaker password if they so choose.
So far what I have is:

import re
pattern = "^.*(?=.{8,})(?=.*\d)(?=.*[a-z])(?=.*[A-Z])(?=.*[@#$%^&+=]).*$"
password = raw_input("Enter string to test: ")
result = re.findall(pattern, password)
if (result):
    print "Valid password"
else:
    print "Password not valid"

Answer 1

import re
password = raw_input("Enter string to test: ")
if re.fullmatch(r'[A-Za-z0-9@#$%^&+=]{8,}', password):
    # match
else:
    # no match

The {8,} means "at least 8". The .fullmatch function requires the entire string to match the entire regex, not just a portion.