How to save a dictionary over multiple uses

[Jonah]

I am creating a login script and I store the usernames and passwords in a dictionary. The problem is though, when I open it a second time it doesn't store the users that have already been registered. I know this is normal but is there a way to get round that? Perhaps using a file?

Note: I asked this on Stackoverflow and got no answer so i am re asking. That is why I am trying to use Pickle.

Here is my code:

import os
import sys
users={}
status=""
 
def login():
    status=raw_input("Are you a new user?")
    if status=="y"
        createnewuser=raw_input("Create username: ")
        if createnewuser in users:
            print "User already exists!"
        else createpsswrd=raw_input("Create new password")
            users[createnewuser]=createpsswrd 
            print "Register successful!"
    elif status == "n":
        login=raw_input("Username: ")
        passw=raw_input("Password: ")
        if login in users and users[login]==passw:
            print "Login successful!"
            os.system("python file.py")
            return
        else:
            print "Username and password do not match."
try:
    with open('file') as infile:
        cPickle.load(infile)
except:
    users = {}
 
while status != "q":
    login()
 
with open('file') as outfile:
    cPickle.dump(users, outfile)

Results: I get through the entire script with no errors but the outfile file has nothing written on it. The dictionary doesn't save across sessions. I am using Raspian on a raspberry Pi 2 if that matters.

[dwblas]

You don't catch the input from cpickle.load(). Simple example at https://wiki.python.org/moin/UsingPickle Note also that you open the output file as a read/input file (the default), when it should be "wb", write, binary. You may have not gotten any responses because of the title. It looks like a code snippet (a Howto), not a question, and if you already know "How to save a dictionary" then you don't even look at the thread (as I almost did here).