Using regex to validate passwords

Question

I was trying to validate the strength of passwords in this way using regex at least: one number, one special character, at one Capital Letter, and 8 characters long.

I thought these would do:

re.compile(r'[a-zA-Z0-9+-!._]{8,}')
re.compile(r'(_\.\+\-!\?)+[a-z]+[A-Z]+[0-9]+')

However, both aren't working: the first one doesn't calculate the 'at least' rule, while the second only matches in a specific order, which is useless.

How can we do that? Your answer would clarify much about practical use of regular expressions.

Answer 1

one number, one special character, at one Capital Letter, and 8 characters long.

((?=.*\d)(?=.*\W)(?=.*[A-Z]).{8,})

you can check your regex at https://regex101.com/
to learn regex is here https://regexr.com/