[Tutor] email validation

[Emile van Sebille]

On 8/1/2015 10:54 AM, Quiles, Stephanie wrote:
> Hello All,
>
> I have a python assignment. I have to make sure that when user inputs email that the program verifies that the address as a @ and a “.” in the entry or else return an invalid email error.
> A Very rudimentary form of email validation. i cannot get the program to work. Here is what i have so far:
>
> import pickle
>
>
> def main():
>      cont = True
>      emails = open_existing_file()
>      print(emails)
>
>      # Get data...
>      while cont:
>          name = input("Enter your name :")
>          email1 = input("Enter your email address :")
>          email2 = input("Enter alternate email address :")
>          phone  = input("Enter your phone number :")
>          contactlist = [email1,email2,phone]
>          emails[name] = contactlist
>          c = input("Enter another? [y]/n :")
>          if c == 'n' or c == 'N':
>              cont = False
>
>          def email1():
>              if '@' not in email and '.' not in email:
>                  print('email needs @ and . at the same time')
>      # Save data...
>              outfile = open("emails.dat","wb")
>              pickle.dump(emails,outfile)
>              outfile.close
>              print("Your data has been saved to emails.dat")
>
>      def open_existing_file():
>      # returns an empty dictionary or one that has data from a file
>          emails = {}
>      # Load the dictionary
>      try:
>          infile = open("emails.dat","rb")
>          emails = pickle.load(infile)
>          infile.close()
>      except:
>          print("No file to open. Starting with no data.")
>      return emails
>
> main()
>
> Here is the error message :
>
> /Library/Frameworks/Python.framework/Versions/3.4/bin/python3.4 /Users/stephaniequiles/Downloads/emailsupdate.py
> Traceback (most recent call last):
>    File "/Users/stephaniequiles/Downloads/emailsupdate.py", line 42, in <module>
>      main()
>    File "/Users/stephaniequiles/Downloads/emailsupdate.py", line 6, in main
>      emails = open_existing_file()
> UnboundLocalError: local variable 'open_existing_file' referenced before assignment
>
> Process finished with exit code 1
>
> not sure why it is not recognizing that the open_existing_file() function needs to be returned to the “emails” variable? I am guessing it has to do with my syntax? any suggestions, please?

Python executes as it processes the file, so that open_existing_file 
must have been previously defined before you can refer to it.  Try 
moving that def block in front of main and you'll likely be OK (assuming 
no other issues)

Emile