Password validation - at least one capital, one lower case and one number

Question

How would I validate an input to check if it contains at least 1 number, ONE CAPITAL letter and one lower case letter. I have looked through similar questions and they don't seem to be exactly what I need e.g only checking for numbers and rejecting letters, I need it to except anything with more than one number, capital letter and lower case letter.

https://stackoverflow.com/questions/7684815/regex-for-alphanumeric-with-at-least-1-number-and-1-character — user2341726, Aug 15 '17 at 14:36
https://stackoverflow.com/questions/41117733/validation-a-password-python duplicate? — Vinujan.S, Aug 15 '17 at 14:40
I would suggest using regex to get your results, in the fastest possible way. I learned it through: [regexr.com] — BikerDude, Aug 15 '17 at 14:40

score 0 · Answer 1 · answered Aug 15 '17 at 14:46

You can use assert combined with any() and string built-in module like this:

import string

password = '1Aa'

try:
    assert any(i in string.ascii_lowercase for i in password)
    assert any(i in string.ascii_uppercase for i in password)
    assert any(i in string.digits for i in password)
except AssertionError as e:
    raise Exception('Invalid password!')

user8435959 · Answer 2 · 2017-08-15T14:52:34.907

0

import re
def passwordagain():
password()

def password():
        print()
        password = input("Enter a secure password: ")
        if   re.search('[A-Z]',password) is None:
            print("Password must contain at least one capital letter and one number.")
            passwordagain() 
        elif re.search('[0-9]',password) is None:
            print("Password must contain at least one capital letter and one number.")
            passwordagain() 
        elif re.search('[a-z]',password) is None: 
            print("Password must contain at least one capital letter and one number.")
            passwordagain()          
        else:
            filename = ("password.");
            with open (filename, "w") as f:
                f.write (password)
            print()
            print("Password saved")

edited Aug 15 '17 at 14:52

answered Aug 15 '17 at 14:48

user8435959

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what is `passwordagain()`? – asongtoruin Aug 15 '17 at 14:51
sorry missed that out, it is just a way to loop the function – user8435959 Aug 15 '17 at 14:52
That's not a very sensible way to initiate an infinite loop. You should look into the use of `while True:` - [this question and answer](https://stackoverflow.com/questions/3754620/a-basic-question-about-while-true) might help – asongtoruin Aug 15 '17 at 14:55

Password validation - at least one capital, one lower case and one number

2 Answers2