Python Programming Lecture Notes - Password Generator Project

Previous Projects

• Rock, Paper, Scissors Game
  • Simple game project discussed earlier.

Current Project Description

• Project: Password Generator Program
• Objective: Use knowledge gained so far (loops, random module, etc.) to create a password generator.
• Levels:
  • Easy Level: Characters (letters, symbols, numbers) in a fixed order.
  • Hard Level: Characters shuffled for increased security.

Expected Output

1. Welcome message: "Welcome to the Password Generator!"
2. Prompt user for password components:
   • Number of letters
   • Number of symbols
   • Number of numbers
3. Generate password according to user specifications:
   • Example: If 4 letters, 3 symbols, 2 numbers are requested, an example password could be eSn9%#().
   • Passwords can include:
     • Lowercase letters
     • Uppercase letters
     • Symbols
     • Numbers

Password Generation Logic

• Importing Random Module: Use functions like random.choice and random.shuffle.
• Lists Creation: Lists for letters (both cases), numbers, and symbols.
• User Input: Take user input for the amount of each character type in the password.
• Looping: Use loops to generate each component of the password.
• String Concatenation: Combine generated characters into a single password string (easy level).
• Shuffling (Hard Level): Use random.shuffle to shuffle the characters in the generated list for a strong password.

Implementation Steps

1. Import Module: import random
2. Create Lists:
   • Letters: letters = ['a', 'b', 'c', ..., 'A', 'B', 'C', ...]
   • Numbers: numbers = ['0', '1', '2', ..., '9']
   • Symbols: symbols = ['!', '@', '#', ...]
3. Print Welcome Message:
   • print("Welcome to the Password Generator!")
4. Take User Input:
   • Using input() and converting to integers.

     n_letters = int(input("How many letters? "))
     n_symbols = int(input("How many symbols? "))
     n_numbers = int(input("How many numbers? "))
     

5. Generate Characters: Separate loops for letters, symbols, and numbers.
   • Example for letters:

     password = ""
     for _ in range(n_letters):
         password += random.choice(letters)
     

6. Combine All Components: Append generated symbols and numbers.
   • Example:

     for _ in range(n_symbols):
         password += random.choice(symbols)
     for _ in range(n_numbers):
         password += random.choice(numbers)
     

7. Shuffle for Hard Level:
   • Convert password string to list and shuffle:

     password_list = list(password)
     random.shuffle(password_list)
     password = ''.join(password_list)
     

8. Print Final Password: Display the generated password:
   • print("Your password is: ", password)

Important Points to Remember

• Understand logic before coding: Consider making a flowchart.
• random.choice(): Selects random elements from a list.
• random.shuffle(): Shuffles elements in a list.
• String Concatenation: Use += for combining characters.
• Use loops and range functions effectively.
• Convert data types where needed (e.g., inputs to integers).

Try It Yourself

• Easy Level: Generate passwords with components in a fixed order.
• Hard Level: Shu""
• Dry Run: Write down and trace through each line of code manually for understanding.