Basic log-in system

[kiere234]

i am needing some help on a few things:
1 - how to load new data into a text file for a new user
2 - I need to have a function called change password and I cant get the code to work to change a value in a dictionary/text file.

The following is my code:

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79

def main():     ok, name = checkLogin()     if ok:         print("Welcome", name.upper())         runMenu()     else:         print("OOPs, failed to login...")     print("BYE!!!") #end def-----------------   def checkLogin():     global users, uName, pWord     users = {"admin":{'pwd':"admin",'valid':"VALID", 'fName':"root"}, "fred":{'pwd':"fred", 'valid':"VALID", 'fName':"Fred", 'sName':"Smith"}}       with open("UserDetails.txt", 'w') as dFile:         for k, v in users.items():             dFile.write(k + " | ")             for innerKey, detail in v.items():                 dFile.write(innerKey + " | " + detail + " | ")             dFile.write("\n")       validUser = False     numAttempts = 0     while (not validUser) and numAttempts < 3:         uName = input("username >>  ")         pWord = input("password >>  ")         if uName in users and pWord in users[uName].values():             validUser = True             return True, users[uName]['fName']         else:             numAttempts += 1       if uName in users:         users[uName]['valid'] = "INVALID" #NEED None ADDING TO THIS RETURN…     return False, None #end def-----------------   def runMenu():     choice = ' '     choices = [None , addUser, changePassword, viewUserDetails, listAllUsers] ## sneaky bit of magic python. This is a list of function names...     while choice != '5':         choice = displayMenu() # THE IF STATEMENT NEEDS TO BE INSIDE THE WHLE LOOP…         if '1' <= choice <='4': choices[int(choice)]() ## calls the function at the relevant position on the list (just add the round brackets)         elif choice != '5': print("input not recognised. please try again...") #end def-----------------   def displayMenu():     print("\nWhat would you like to do:")     options = ["add user", "change password", "view user details", "list all users", "quit"]     optionString = ""     for k, option in enumerate(options):         optionString += str(k+1) + ") " + option + "\n"     return input(optionString + ">>  ").strip()[0] #end def-----------------   def addUser():     global allLines, Uname, fname, sname     print("adding user......")       Uname = input("Please enter a username >>>")     Npwd = print(createPassword(3))     fname = input("Please enter your first name >>>")     sname = input("Please enter your second name >>>")     users[Uname] = {'pwd':Npwd, 'fName':fname, 'sName':sname}       with open("UserDetails.txt", 'w') as dFile:         for k, v in users.items():             dFile.write(k + " | ")             for innerKey, detail in v.items():                 dFile.write(innerKey + " | " + detail + " | ")             dFile.write("\n")     #end def-----------------   def changePassword():     print("changing Password......")