Question

When I run this code in the command prompt, the Person I create is automatically deleted, but when in IDLE the deletion does not occur. Why?

NOTE: This is a program that is supposed to create an address book (a list of dictionaries)

Here is my code:
list = []

class bookEntry(dict):
    total = 0

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

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

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

    def __del__(self):
        print '%s has been deleted' % (self.n)

    def addnewperson(self, n, e = '', ph = '', note = ''):
        self.d['name'] = n
        self.d['email'] = e
        self.d['phone'] = ph
        self.d['note'] = note

        list.append(self)

I run the code 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()

When the code is run in IDLE I receive the following prompts, and submit the following answers:

'''
    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
'''

Here, Pig is created and is not deleted. But in cmd…..

'''
    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
    Pig has been deleted
'''

Why is Pig being deleted?? __del__ is never called…

Answer 1

When the program ends, all variables are automatically deleted (otherwise, there would be a memory leak). IDLE keeps the environment open so you can keep using the variables you’ve created.

Note: My original answer was mistaken- I missed the lines

list = []

and

list.append(self)