Python login script using dictionary

Question

I am making a login script for python and it will create passwords and write them to a text file like (username:password). But I want to add a login script that will check to see if the username and password is in the text file.

def reg():
    print('Creating new text file') 
    name = input('Username: ')
    passwrd = input('Password: ')
    with open("users.txt", "r+") as f:
     old = f.read()
     f.seek(0)
     f.write(name + ":" + passwrd + "\n" + old)
    f.close()
def login():
    user = input("username: ")
    passwrd = input("password: ")

    with open('users.txt') as f:
       credentials = [x.strip().split(':') for x in f.readlines()]

    for user,passwrd in credentials:
    (This is where i want to add the code)

reg()
login()

I think it would be something like.

for user,passwrd in credentials:
    print("found")
else:
    print("not found")

yes i want to add a piece of code that checks to see if the variables user and passwrd are in the file and if they are print "correct" or "incorrect" — user5134772
– user5134772, Commented Nov 4, 2015 at 20:25
change for user,passwrd to if [user,passwrd] if you want to check whether the inputs are in credentials list — R Nar
– R Nar, Commented Nov 4, 2015 at 20:27

James Harrison · Accepted Answer · 2015-11-04 20:54:11Z

1

If you make credentials a dict, then you can do:

if user in credentials and credentials[user] == password:
   //success
else:
   //failure

This should work for making credentials be a dict

with open('users.txt') as f:
   credentials = dict([x.strip().split(':') for x in f.readlines()])

answered Nov 4, 2015 at 20:54

James Harrison

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Comments

dsh · Accepted Answer · 2015-11-04 20:31:09Z

0

You just check to see if they match. Note that you need to make the variable names different:

for user2,passwrd2 in credentials:
    if (user == user2 and passwrd == passwrd2):
       print ("Passed")

edited Nov 4, 2015 at 20:31

dsh

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answered Nov 4, 2015 at 20:28

ergonaut

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1 Comment

Pynchia Over a year ago

you might want to break/return if there is a match, since I doubt there will another line with the same combination

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