Super Simple Python: Password Generator

Super Simple Python is a series dedicated to creating super simple Python projects for beginners to be able to do in under 15 minutes. In this episode, we’ll be covering how to build an adjustable Python password generator in under 30 lines of code!

For a video version (that’s actually a little longer in code, I optimized the code for this post):

Like many of the projects we’ve built in the Super Simple Python series like the Random Number Generator, the Dice Roll Simulator, Rock Paper Scissors, and the High Low Guessing Game, the Password Generator relies on the random library. Our password generator will also use the string library. These libraries are both native to Python so we don’t have to use pip to install anything.

We’ll start off by importing these libraries.

import random
import string

Defining a Password Generator Function

We’re generating a password so we’ll start off by creating a function that will do that. This function will take five parameters. Four of those parameters will have default values, only one will be required. The length parameter will dictate the length of our password. The other four parameters, lower, upper, digits, and punctuation will tell the program whether we want to include lowercase, uppercase, digits, and punctuation respectively. We’ll set all of these to True by default. 

We’ll start off with an empty string, char, that will hold a representation of all the characters we can choose from to create our password. For each of the lower, upper, digits, and punctuation we’ll add those characters to char if they’re true. The function will then return a string that joins a length number of randomly chosen characters from the char string as our password.

def pw_gen(length, lower=True, upper=True, digits=True, punctuation=True):
    char = ""
    if lower:
        char += string.ascii_lowercase
    if upper:
        char += string.ascii_uppercase
    if digits:
        char += string.digits
    if punctuation:
        char += string.punctuation
    return ''.join(random.choice(char) for _ in range(length))

Allowing the User to Adjust Input

Now that we’ve created a function to generate a random password, we should let the user adjust the password to their needs. Prompt the user for the length of the password they want. We will also if they want to adjust its parameters. If they want to adjust the password parameters, we’ll go through each of the possible parameters and ask if they want to include those characters in their password. We will use y or n for yes or no respectively and adjust our True/False input values for those parameters to the password generator function we created. Finally, we print a randomly generated password.

_length = int(input("How long of a password do you want? "))
adjust = input("Do you want to adjust the password parameters?(y/n) ")
if adjust == "y":
    _lower = input("Do you want lowercase characters?(y/n) ")
    _upper = input("Do you want uppercase characters?(y/n) ")
    _digits = input("Do you want digits?(y/n) ")
    _punc = input("Do you want punctuation?(y/n) ")
    lower = True if _lower == "y" else False
    upper = True if _upper == "y" else False
    digits = True if _digits == "y" else False
    punc = True if _punc == "y" else False
    print(pw_gen(_length, lower, upper, digits, punc))
else:
    print(pw_gen(_length))

If the user doesn’t want to adjust the parameters of the password generator we should see an output like:

If they do choose to adjust the password generator parameters we’ll see an output like:

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