Code for How to Make a Password Generator in Python Tutorial

password_generator.py

from argparse import ArgumentParser
import secrets
import random
import string

# Setting up the Argument Parser
parser = ArgumentParser(
    prog='Password Generator.',
    description='Generate any number of passwords with this tool.'
)

# Adding the arguments to the parser
parser.add_argument("-n", "--numbers", default=0, help="Number of digits in the PW", type=int)
parser.add_argument("-l", "--lowercase", default=0, help="Number of lowercase chars in the PW", type=int)
parser.add_argument("-u", "--uppercase", default=0, help="Number of uppercase chars in the PW", type=int)
parser.add_argument("-s", "--special-chars", default=0, help="Number of special chars in the PW", type=int)

# add total pw length argument
parser.add_argument("-t", "--total-length", type=int, 
                    help="The total password length. If passed, it will ignore -n, -l, -u and -s, " \
                    "and generate completely random passwords with the specified length")

# The amount is a number so we check it to be of type int.
parser.add_argument("-a", "--amount", default=1, type=int)
parser.add_argument("-o", "--output-file")

# Parsing the command line arguments.
args = parser.parse_args()

# list of passwords
passwords = []
# Looping through the amount of passwords.
for _ in range(args.amount):
    if args.total_length:
        # generate random password with the length
        # of total_length based on all available characters
        passwords.append("".join(
            [secrets.choice(string.digits + string.ascii_letters + string.punctuation) \
                for _ in range(args.total_length)]))
    else:
        password = []
        # If / how many numbers the password should contain  
        for _ in range(args.numbers):
            password.append(secrets.choice(string.digits))

        # If / how many uppercase characters the password should contain   
        for _ in range(args.uppercase):
            password.append(secrets.choice(string.ascii_uppercase))
        
        # If / how many lowercase characters the password should contain   
        for _ in range(args.lowercase):
            password.append(secrets.choice(string.ascii_lowercase))

        # If / how many special characters the password should contain   
        for _ in range(args.special_chars):
            password.append(secrets.choice(string.punctuation))

        # Shuffle the list with all the possible letters, numbers and symbols.
        random.shuffle(password)

        # Get the letters of the string up to the length argument and then join them.
        password = ''.join(password)

        # append this password to the overall list of password.
        passwords.append(password)

# Store the password to a .txt file.
if args.output_file:
    with open(args.output_file, 'w') as f:
        f.write('\n'.join(passwords))

print('\n'.join(passwords))