Python - 检查数字，大写，小写字母和特殊字符的输入

Question

I am trying to create a little program in which the user enters a password into the console. The program then checks whether the password is weak, medium or strong depending what the user has typed in.

I need to check how many uppercase, lowercase and numbers have been entered and then tell the user how strong their password is.

I have most of the program completed, but since I haven't really used Python for long I am not too familiar with anything advanced, bear in mind younger people have to understand this code too who are not going to be good at coding themselves.

So far I have:

#Welcome the user to the application.
print("Hello, please enter a password to check how secure it is");

#Set a variable called MinPass and set a value of 6.
MinPass = 6;

#Set a variable called MaxPass and set a value of 12.
MaxPass = 12;

#Set variable EnteredPass and wait for user input
EnteredPass = input("Password: ");

while len(EnteredPass) < MinPass:
    print("Your password is too short, please enter a longer password and try again")
    EnteredPass = input("Password: ");

while len(EnteredPass) > MaxPass:
    print("Your password is too long, please shorten it and try again!");
    EnteredPass = input("Password: ");

Please note, this is for educational purposes only. I'm not planning on making a program in an intent to steal random password. It's for a part of a course that's going on in my school!

Answer 1

This contains a few more-advanced concepts, but should be easy enough to follow:

import string

def long_enough(pw):
    'Password must be at least 6 characters'
    return len(pw) >= 6

def short_enough(pw):
    'Password cannot be more than 12 characters'
    return len(pw) <= 12

def has_lowercase(pw):
    'Password must contain a lowercase letter'
    return len(set(string.ascii_lowercase).intersection(pw)) > 0

def has_uppercase(pw):
    'Password must contain an uppercase letter'
    return len(set(string.ascii_uppercase).intersection(pw)) > 0

def has_numeric(pw):
    'Password must contain a digit'
    return len(set(string.digits).intersection(pw)) > 0

def has_special(pw):
    'Password must contain a special character'
    return len(set(string.punctuation).intersection(pw)) > 0

def test_password(pw, tests=[long_enough, short_enough, has_lowercase, has_uppercase, has_numeric, has_special]):
    for test in tests:
        if not test(pw):
            print(test.__doc__)
            return False
    return True

def main():
    pw = input('Please enter a test password:')
    if test_password(pw):
        print('That is a good password!')

if __name__=="__main__":
    main()

Answer 2

You can use the following functions:-

    isalnum() # To check for alpha numeric characters
    isalpha() # To check for the presence of only alphabets

for eg.

    password = input("Enter the password: ")
    if password.isalnum() == False:
        print "Password should contain atleast one special character or number"
    if password.isalpha() == False:
        print "Password should contains atleast some alphabets."

To check for the presence of capital or small letters you can use this:-

    temp = passsword.lower()
    if temp  == password:
        print "Password should contain atleast one capital letters"

How it Works? Although this code is self-explanatory, there is nothing rocket-science about it, I will explain it since, you seem to be a beginner to me:-

    str.isalnum() returns False if the string contains some non alphabet characters
    str.isalpha() returns false if the string does not contain a single alphabet

By creating

  temp

I am storing a copy of the password which is lowercase. So if the password variable contains some capital letters then the

    temp == password

will return False, and you can find out whether the string contains some capital letters or not. As pointed out by @MartijnPieters, you can use

    if not password.isalnum():

also instead of

    if password.isalnum() == False: 

Although, the first way is more "pythonic"

Answer 3

编写MATLAB代码以检查输入密码的强度，代码应输出：'weak'，'medium'，'strong'和very strong'，具体取决于密码的长度，使用大写和小写字母，使用数字和特殊字符。