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Question

I'm starting my first project (a password manager). What I have done so far is make it so the user can input whether they want to make a new password or look for a password. If they choose to enter a password, the account/purpose for the password and the actual password will be saved to a dictionary. For example, a purpose could be for "yahoo" and the password being "example". That dictionary is then written down in a text file. If the user decides to look for a password, all they would have to do is type in the account for the password. So far everything is working except for the fact that when I enter another password and account, it overwrites the pre-existing password and account instead of adding the new password to the dictionary.

import json

passwords = {

}


prompt = "If you want to make a new password, type 'Make password'."
prompt += "\nIf you want to look for a password, type 'Look for password'.\n"
answer = input(prompt)


def password_list(account_name, password_name):

    passwords[account_name] = password_name


answer = answer.upper()

found = 0 # used to see whether account for password can be found

if answer == "MAKE PASSWORD":
    account_name = input("What use is this password for? ")
    account_name = account_name.upper()
    password_name = input("What is the password? ")
    password_list(account_name, password_name) # purpose and password saved to dict
    with open("passwords.txt", 'w+') as f:
        f.write(json.dumps(passwords))
    print("Your password was saved!") # dictionary gets saved to text file
elif answer == "LOOK FOR PASSWORD":
    with open("passwords.txt", "r") as f:
        passwords = json.loads(f.read()) # text file gets opened to read
        if not passwords:  # if the list is empty...
            print("Sorry but there are no passwords available. Make a new one!")
        elif passwords:  #if the list isn't empty...
            search_account = input("What account is this password for? ")
            search_account = search_account.upper() 
            for name in passwords.keys():  # list of accounts get searched
                if search_account == name:  #if an account is in the dictionary
                    print(f"The password is '{passwords.get(name)}'.")
                    found = 1
                    break
            if found != 1:
                print("Sorry, we can't find such name.")

Answer 1

"You should probably initialize your password list by reading your json file if it's there. Otherwise, when you run MAKE PASSWORD, it adds the new password to an empty dict and overwrites the existing password file which might've had a password in there before." – rchome

Answer 2

Cool project.

It's because every time you start the script you force the password dic to be empty. So when you add a password, it's added to a new empty dic and than you overwrite the file with this empty dic + new_password.

When you code, think about the most likely outcome at every run: the file exists. IF it doesn't, than create it.

This is what I demonstrate here in the load_passwords() function.

As an extra, I propose to you a more Pythonic (and efficient) way to search through a dictionary's keys in O(1) rather than O(n).

import json

prompt = "If you want to make a new password, type 'Make password'."
prompt += "\nIf you want to look for a password, type 'Look for password'.\n"
answer = input(prompt).upper()

def load_passwords():
    try:
        with open("passwords.txt", "r") as f:
            passwords = json.loads(f.read()) # text file gets opened to read
        return passwords
    except FileNotFoundError:
        print("Sorry but there are no passwords available. Make a new one!")
        return {}

def password_list(account_name, password_name):
    passwords = load_passwords()
    passwords[account_name] = password_name
    return passwords

if answer == "MAKE PASSWORD":
    account_name = input("What use is this password for? ").upper()
    password_name = input("What is the password? ")
    passwords = password_list(account_name, password_name) # purpose and password saved to dict
    with open("passwords.txt", 'w+') as f:
        f.write(json.dumps(passwords))
    print("Your password was saved!") # dictionary gets saved to text file


elif answer == "LOOK FOR PASSWORD":
        passwords = load_passwords()

        if passwords:  #if the list isn't empty...
            search_account = input("What account is this password for? ").upper()

            # this is much better
            if search_account in passwords:
                print(f"The password is '{passwords.get(search_account)}'.")
            else:
                print("Sorry, we can't find such name.")

Note: Be sure to encrypt your passwords before saving to a file.