python读/写文件登录脚本

Question

I was wondering if anyone would help. I am new to python. I am trying to create a basic login script for a game, that will write a username and password to a text file. When logging in, it will read from that text file and compare the entry made by the user. The code is below:

def Register():
    print("Hello! You need to register an account before you can begin")
    username = input("Please enter a username: ")
    password = input("Now please enter a password: ")
    file = open("Login.txt","a")
    file.write (username)
    file.write (",")
    file.write (password)
    file.write("\n")
    file.close()
    print ("Your login details have been saved. ")
    print("You will now need to login")
    Login() 

def Login():
    print("Please enter your details to log in")
    username1 = input("Please enter your username: ")
    password1 = input("Please enter your password: ")

    file = open("Login.txt","r")

    for row in file:
        field = row.split(",")
        username = field[0]
        password = field[1]
        lastchar = len(password)-1
        password = password[0:lastchar]
        print(username,password)

        if username1 == username and password1 == password:
            print("Hello",username)

        else:
            print("incorrect")

#file.close()


 user=input("Are you already a user? ")

 if user == "Yes":
     Login()

 elif user =="No":
     Register()

 print("Welcome to our game")

I have entered the second user who is stored in the text file, It seems to be working but it checks my first entry and says its incorrect and then loops to the second entry. This is the output I keep getting:

Are you already a user? Yes
Please enter your details to log in
Please enter your username: jen
Please enter your password: ben
tess bess
incorrect
jen ben
Hello jen
Welcome to the dice game
>>> 

Does anyone have an idea on how to only display the entry you have entered?

Thanks

Answer 1

Like Sharku said, put the print(username,password) in your if below. Also writting clearly the name and password of the user after he typed it isn"t really a smart moove, delete it and just let your message when a user is logging in !

for row in file:
    field = row.split(",")
    username = field[0]
    password = field[1]
    lastchar = len(password)-1
    password = password[0:lastchar]

    if username1 == username and password1 == password:
        print("Hello",username)

    else:
        print("incorrect")

Answer 2

As said by sytech, you could use the break and else clauses of the for loop:

for row in file:
    field = row.split(",")
    username = field[0]
    password = field[1]
    lastchar = len(password)-1
    password = password[0:lastchar]

    if username1 == username and password1 == password:
        print("Hello",username)
        break
else:
    print("incorrect")

Answer 3

Your 'for loop' will loop through each entry in your file, that means for each entry in the file your for loop prints the entry due to this line:

    print(username,password)

If you don't want it to print all values in the file remove this line of code. Adding a 'break' to your if statement, as suggested by others, will mean that as soon as your loop has found the entry that matches the one entered by the user it will leave the loop and not continue going through all values unnecessarily.

You could do something like this:

    if username1 == username and password1 == password:
        print("Hello",username)
        break

    else:
        continue

This means that when a user input doesn't match an entry in the file the loop will just continue till it finds a match. However, your code doesn't take into consideration if a user doesn't exist.

Answer 4

import os.path

if not os.path.exists('register.txt'):
    file = open('register.txt', 'w')
    file.close()


def register():
    username = input('Enter username: ')
    if username in open('register.txt', 'r').read():
        print('Username already exists')
        exit()
    password = input('Enter password: ')
    c_password = input('Enter confirm password: ')
    if password != c_password:
        print('Sorry password not match')
        exit()
    handle = open('register.txt', 'a')
    handle.write(username)
    handle.write(' ')
    handle.write(password)
    handle.write('\n')
    handle.close()
    print('User was successfully registered')
    exit()


def login():
    username = input('Enter username: ')
    password = input('Enter password: ')
    get_data = open('register.txt', 'r').readlines()
    users_data = []
    for user in get_data:
        users_data.append(user.split())

    total_user = len(users_data)
    increment = 0
    login_success = 0
    while increment < total_user:
        usernames = users_data[increment][0]
        passwords = users_data[increment][1]
        if username == usernames and password == passwords:
            login_success = 1

        increment += 1

    if login_success == 1:
        print('Welcome ' + username)
    else:
        print('invalid username & password')


question = input('Do you have an account?/yes/no')

if question == 'yes':
    login()
else:
    register()