Question

I’m trying to write a program that creates an address book with contact names, emails, phone numbers, etc. I store each contact as a dictionary and then place each person (dictionary) into a global list. I then convert the list to a string using repr() and write it to a file. When I try to reload the list and write what it contains, I get a list of empty dictionaries. Please help me figure out what is wrong.

Here is my code:

list = []
listfile = 'phonebook.txt'

class bookEntry(dict):
    total = 0

    def __init__(self):
        bookEntry.total += 1
        self.d = {}

    def __del__(self):
        bookEntry.total -= 1

class Person(bookEntry):
    def __init__(self, n):
        bookEntry.__init__(self)
        self.n = n
        print '%s has been created' % (self.n)

    def addnewperson(self, n, e = '', ph = '', note = ''):
        f = file(listfile, 'w')

        self.d['name'] = n
        self.d['email'] = e
        self.d['phone'] = ph
        self.d['note'] = note

        list.append(self)
        listStr = repr(list)
        f.write(listStr)

        f.close()

I start the program with a startup() function:

def startup():
    aor = raw_input('Hello! Would you like to add an entry or retrieve one?')
    if aor == 'add':
        info = raw_input('Would you like to add a person or a company?')
        if info == 'person':
            n = raw_input('Please enter this persons name:')
            e = raw_input('Please enter this persons email address:')
            ph = raw_input('Please enter this persons phone number:')
            note = raw_input('Please add any notes if applicable:')

            X = Person(n)
            X.addnewperson(n, e, ph, note)
startup()

I add these answers to the prompts:

'''
    Hello! Would you like to add an entry or retrieve one?add
    Would you like to add a person or a company?person
    Please enter this persons name:Pig
    Please enter this persons email address:[e-mail]
    Please enter this persons phone number:333-333-3333
    Please add any notes if applicable:one of three
    Pig has been created
'''

When I open phonebook.txt, this is what I see:

[{}]

Why are empty dictionaries being returned?

Answer 1

You’re deriving from dict, but storing all the elements in a member d. Hence, repr gives you a string representing an empty dict. If you want to use a bookEntry as a dict, insert the info with

self['name'] = n

instead of

self.d['name'] = n

(But really, you shouldn’t be inheriting from dict here. Also, please don’t use list as an identifier, it’s the name of a builtin.)