Question

This is a homework question, but as you can see I’ve written most of the code already. 🙂 What I’m trying to have happen is that the Agent object inherits the methods from the Investor object, as the Agent object’s methods are suppose to be basically the same. The only different is the constructors, Investor takes 6 parameters, Agent takes 7. You can see that the parameters are also basically the same.

Investor.load and Investor.report work, for the most part, as expected. The inherited methods in Agent do not. See below.

My main issues:

1. When I run report(o) on Investor, the output is slightly messed up. It has little paragraph symbols at the end of each line, rather than a carriage return. (I’m developing on linux)
2. When I run load and report on Agent, it does not populate my arrays (reports and data) as it should. Because of that, report prints nothing. How do I set up my class variables so that they work in the way I want them to?

Thanks!

Will re-add after turnin date.

Here is how the above code SHOULD function.

>>> from sys import stdout as o
>>> import datetime
>>> from hedgefunds import *
>>>
>>> i = Investor('Flintstone','Fred',datetime.date(1965,12,3),'male','Mr.')
>>>
>>> i
Investor('Flintstone', 'Fred', datetime.date(1965, 12, 3), 'male', 'Mr.', 1)
>>> repr(i)
"Investor('Flintstone', 'Fred', datetime.date(1965, 12, 3), 'male', 'Mr.', 1)"
>>> i.__repr__()  # THIS CONTROLS PREVIOUS TWO LINES
"Investor('Flintstone', 'Fred', datetime.date(1965, 12, 3), 'male', 'Mr.', 1)"
>>> eval(repr(i))  # OBJECT CAN BE RECREATED FROM ITS REPR STRING
Investor('Flintstone', 'Fred', datetime.date(1965, 12, 3), 'male', 'Mr.', 1)
>>>
>>> i  # NOTICE ONE ADDITIONAL BIT OF DATA WE DIDN'T SPECIFY?
Investor('Flintstone', 'Fred', datetime.date(1965, 12, 3), 'male', 'Mr.', 1)
>>> # THE '1' AT THE END IS THE RECORD ID rid. THE REPR STRING INCLUDES ALL DATA SO YOU SEE IT.
>>> # THE INVESTOR CLASS SHOULD ASSIGN A rid IF ONE IS NOT PASSED INTO THE CONSTRUTOR.
>>>
>>> print i
1, Mr. Fred Flintstone, 12/03/1965, male
>>> i.__str__()  # THIS CONTROLS PREVIOUS LINE
'1, Mr. Fred Flintstone, 12/03/1965, male'
>>>
>>> # NOTE THE NAME IS NICELY PUT TOGETHER AND AND rid IS AT THE START
>>> # NOTE datetime.date(YYYY, MM, DD) BUT WE PRINT IN  MM/DD/YYYY FORMAT
>>>
>>> # NOW LET'S LOOK AT OUR INVESTOR OBJECT'S ATTRIBUTES
>>> i.last_name
'Flintstone'
>>> i.first_name
'Fred'
>>> i.dob
datetime.date(1965, 12, 3)
>>> i.date_of_birth
'12/03/1965'
>>> i.gender
'male'
>>> i.title
'Mr.'
>>> i.name
'Mr. Fred Flintstone'
>>> i.rid
1 
>>>
>>> # BUT WE'RE GONNA NEED SOMEHWERE TO STORE MULTIPLE INVESTOR OBJECTS
>>> # SO AS WELL AS CREATING INVESTOR OBJECTS, THE INVESTOR CLASS MUST ACT LIKE A RECORDSET
>>>
>>> Investor.report(o)  # o WAS SET TO STDOUT AT THE TOP OF THIS TRACE BUT COULD BE ANY FILE
>>> Investor.add(i)  # NO RECORDS SO LET'S ADD ONE
>>> Investor.report(o)  # NOW WE HAVE SOMETHING TO REPORT
1, Mr. Fred Flintstone, 12/03/1965, male
>>>
>>> Investor.add(Investor('Flintstone','Wilma',datetime.date(1968,1,15),'female','Mrs.'))
>>> Investor.report(o)
1, Mr. Fred Flintstone, 12/03/1965, male
2, Mrs. Wilma Flintstone, 01/15/1968, female
>>>

>>> # WE COULD CONTINUE ADDING INVESTORS MANUALLY BUT SINCE WE'VE GOT A FILE FULL OF THEM....
>>> Investor.load('investors.csv')
>>> Investor.report(o)
1, Mr. Charles Creed, 12/05/1928, male
2, Miss Sheila Geller, 11/12/1962, female
3, Mr. Fred Kenobi, 07/13/1957, male
4, Miss Rachel Geller, 07/11/1968, female
5, Mr. Charles Rubble, 09/23/1940, male
6, Mrs. Leah Skywalker, 07/02/1929, female
7, Mr. Bill Balboa, 03/06/1988, male
8, Dr. Sheila Barkley, 08/26/1950, female
.
.
>>> # YOU SHOULD SEE 120 RECORDS (OUR TWO MANUALLY ADDED RECORDS ARE GONE)
>>>
>>>
>>>
>>> # AGENTS
>>>
>>> a = Agent(2.1,'Rubble','Barney',datetime.date(1966,4,20),'male','Mr.')
>>> a
Agent(2.1000000000000001, 'Rubble', 'Barney', datetime.date(1966, 4, 20), 'male', 'Mr.', 1)
>>> repr(a)
"Agent(2.1000000000000001, 'Rubble', 'Barney', datetime.date(1966, 4, 20), 'male', 'Mr.', 1)"
>>> eval(repr(a))
Agent(2.1000000000000001, 'Rubble', 'Barney', datetime.date(1966, 4, 20), 'male', 'Mr.', 1)
>>> print a
1, Mr. Barney Rubble, 04/20/1966, male, 2.1
>>> a.last_name
'Rubble'
>>> a.first_name
'Barney'
>>> a.dob
datetime.date(1966, 4, 20)
>>> a.date_of_birth
'04/20/1966'
>>> a.gender
'male'
>>> a.title
'Mr.'
>>> a.name
'Mr. Barney Rubble'
>>> a.rid
1
>>> a.commission
2.1000000000000001
>>> Agent.add(a)
>>> Agent.report(o)
1, Mr. Barney Rubble, 04/20/1966, male, 2.1
>>> Agent.load('agents.csv')
>>> Agent.report(o)
1, Mr. Barney Flintstone, 02/13/1933, male, 4.0
2, Miss Rachel Rubble, 11/21/1982, female, 2.5
3, Dr. Ted Geller, 03/14/1963, male, 8.0
4, Miss Phoebe Creed, 11/06/1959, female, 5.5
5, Mr. Luke Kenobi, 08/24/1945, male, 2.5
6, Dr. Megan Creed, 03/26/1957, female, 5.5
7, Mr. Ted Rubble, 09/14/1931, male, 3.5
8, Mrs. Monica Balboa, 05/07/1934, female, 1.5

Answer 1

There is a lot going on here, so I’ll try to be brief.

class Investor(object):
    reports = []
    data = []

    def __init__(self, LastName, FirstName, Date, Gender, Title, Rid=1):
        # the following two lines define variables which only exist inside
        # __init__, so they can basically be gotten rid of.
        # reports = []
        # data = []
        # but they *don't need to be initialized*. Actually creating a new list
        # in each constructor is *bad* unless you want one report per instance

        # ... later, be sure to add "self" instead of adding to the local vars
        self.add(self)

    @classmethod
    def report(self, o):
        result = ""
        for x in self.reports:
            # Just use join, that's what you mean anyway.
            result = ', '.join(x)
            # \n should result in \n\n. I think you mean o.write(result)
            o.write(result + "\n")

    @classmethod
    def load(self, f):
        self.reports = []
        self.data = []
        file = open(f)
        # why the extra readline?
        file.readline()
        list = []
        while 1:
            line = file.readline()
            # you need to get rid of the trailing whitespace
            items = line[:-1].split(", ")
            if not line:
                break
            else:
                # self, here, refers to the class, so you can use it as the
                # constructor as well
                # use the * to make a list into an argument list.
                self(*items)
                # No need to add it, the value is added at the end of __init__
                # as things stand.

class Agent(Investor):
    reports = []
    data = []

    def __init__(self, Commission, LastName, FirstName, \
                       Date, Gender, Title, Rid=1):
        super(Agent, self).__init__(self, LastName, FirstName, Date, \
                                          Gender, Title, Rid)
        self.commission = Commission

    def __str__(self):
        # Be lazy! Use super!
        return super(Agent,self).__str__() + ', ' + self.commission

    # this was doing the same thing in the parent class.
    # def __repr__(self):

    # The classmethod methods are not needed unless you want to redefine 
    # behavior in a child class.
    @classmethod
    def add(self, i):
        # If you do change something, though, make sure to use super
        # here as well...
        super(Agent, self).add(i)

I believe that should take care of most of your issues.

If you want to have the format Investor('Flintstone', 'Fred', datetime.date(1965, 12, 3), 'male', 'Mr.', 1), you’ll need to include the __name__ and quote the properties:

def __repr__(self):
    # notice the " and ' below.
    return self.__name__ + "('" + str(self.rid) + "', '" + \
           self.name + "', " + self.date_of_birth + ", '" + self.gender + "')"

In Agent you will need to use a sub-string to get what you need:

def __repr__(self):
   # remove the Agent( so you can add the commission at the *front* 
   s = super(Agent,self).__str__()
   return self.__name__ + "('" + self.commission + "'," + \
          s[len(self.__name__ + 1):]