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Creating a Password Strength Checker with Python

June 20, 2022

In this activity, you will create a validation function for checking the strength of a password. The focus of this activity is the logic behind the checker.

Password strengths are as follows:

• A very weak password contains 6 or fewer characters, consisting only of numbers.
• A very strong password has more than 6 characters, consisting of at least one number and at least one letter.
• Any other type of password is of average strength.

Starter file

# Import the `string` library.


# Use the `string` library to initialize string variables representing all valid letters and digits, respectively.


# Define a function called `check_strength` that takes in a string parameter called `password`.

    # Create two boolean variables called `contains_number` and `contains_letter`. Set them to False.


    # Initialize a `count` variable and set it to 0.


    # Loop through each character in the `password` and increment the `count` variable by 1 for each character.


        # Create an if-else statement that loops through each character in `password` and updates `contains_number` or `contains_letter` to True.


    # If `password` contains equal to or fewer than 6 characters and consists only of numbers, print "Your password is too weak."
    # Else if `password` contains more than 6 characters and consists of at least one number and at least one letter, print "Your password is a strong password".
    # Else, print "Your password is of average strength."


# Declare a variable as `user_input_password` with an input stating "Input your password: ".


# Call the check_strength function with the `user_input_password`.

Instructions

Open the starter file and perform the following:

1. Import the string library.
2. Use the string library to initialize string variables representing all valid letters and digits, respectively.
3. Define a function called check_strength that takes in a string parameter called password.
   • Create two Boolean variables called contains_number and contains_letter. Set them to False.
   • Initialize a count variable and set it to 0.
   • Loop through each character in the password and increment the count variable by 1 for each character.
   • Create an if-else statement that loops through each character in password and updates contains_number or contains_letter to True.
4. Create an if-else statement for the following:
   • If password contains 6 or fewer characters and consists only of numbers, print “Your password is too weak”.
   • Else if password contains more than 6 characters and consists of at least one number and at least one letter, print “Your password is a strong password”.
   • Else, print “Your password is of average strength”.
5. Declare a variable as user_input_password with an input stating “Input your password:”
6. Call the check_strength function with user_input_password.

Solution

# Import the `string` library.
import string

# Use the `string` library to initialize string variables representing all valid letters and digits, respectively.
valid_characters = string.ascii_letters
valid_numbers = string.digits

# Define a function called `check_strength` that takes in a string parameter called `password`.
def check_strength(password):
    # Create two boolean variables called `contains_number` and `contains_letter`. Set them to False.
    contains_number = False
    contains_letter = False

    # Initialize a `count` variable and set it to 0.
    count = 0

    # Loop through each character in the `password` and increment the `count` variable by 1 for each character.
    for character in password:
        count += 1

        # Create an if-else statement that loops through each character in `password` and updates `contains_number` or `contains_letter` to True.
        if character in valid_characters:
            contains_letter = True
        elif character in valid_numbers:
            contains_number = True

    # If `password` contains equal to or fewer than 6 characters and consists only of numbers, print "Your password is too weak."
    # Else if `password` contains more than 6 characters and consists of at least one number and at least one letter, print "Your password is a strong password".
    # Else, print "Your password is of average strength."
    if count <= 6 and contains_number == True and contains_letter == False:
        print("Your password is too weak.")
    elif count > 6 and contains_number == True and contains_letter == True:
        print("Your password is a strong password.")
    else:
        print("Your password is of average strength.")

# Declare a variable as `user_input_password` with an input stating "Input your password: ".
user_password = input("Input your password: ")

# Call the check_strength function with the `user_input_password`.
check_strength(user_password)