Homework 10: Object-Oriented Programming

Object-Oriented Programming
Python is an object-oriented programming language. That means it provides features
that support object-oriented programming (OOP). Object-oriented programming has its
roots in the 1960s, but it wasn’t until the mid 1980s that it became the main
programming paradigm used in the creation of new software.
In object-oriented programming the focus is on the creation of objects, which contain
both data and functionality together. Usually, each object definition corresponds to
some object or concept in the real world and the functions that operate on that object
correspond to the ways real-world objects interact. We’ve already seen classes like
Math, Random, and many others. We are now ready to create our own user-defined
class.
[http://openbookproject.net/thinkcs/python/english3e/classes_and_objects_I.html]
Introduction
The goal of this homework is for you to showcase your knowledge about how to
properly use OOP. For this assignment you will need to implement 2 classes. Refer to
the rubric to see how points will be rewarded for each function. You have been given
HW10.py to fill out with instructions in the docstrings. However, below you will find more
detailed information to complete your assignment. Read it thoroughly before you begin.
Don’t forget to include your name and your collaboration statement. Re-download your
submission from T-Square after you submit it to make sure that your code runs
successfully.
User
The User class can be used to create different instances which each represent a user of
LinkedIn. Each user should have a name, a current employer (if specified), skills, and
connections. You will be writing methods that allow you to alter the user’s attributes and
interact with other User objects.
Attributes
● name: The name of the user
● skills: The skills that the user has mapped to a list of other
users who have endorsed the user for the skill
● company: The company that the user currently works for
● connections: A list of of users the user is connected with
Methods
__init__()
● name: <string
● skills: dictionary with KEY - skill <str: VALUE - endorsers
<list of User objects pairs. Users start out with this
attribute being None, unless specified during instantiation.
● company: company <Company object that the user currently works
for. This attribute should be None until a user is hired by a
company (see Company class)
● connections: <list of connections (User objects). Users start
out with an empty list
__repr__()
● Return string representation of User in the following format:
● “A User named [name], employed by [Company]/unemployed, skilled
in [most-endorsed skill; alphabetically first if there’s a
tie]/nothing if no skills, with [num connections] connections”
● Example 1: if we have a User named Bob who is unemployed, and
has no skills or connections, this method should return “A User
named Bob, unemployed, with 0 connections”
● Example 2: if we have a User named Jane who is employed by
Facebook, has Python as her most-endorsed skill, and has 10
connections, this method should return “A User named Jane,
employed by Facebook, skilled in Python, with 10 connections”
● HINT: Use string formatting and if statements to match this
format exactly!
● HINT: When you print a list of User objects, you will see a
list of their string representations as defined in the __repr__
function. Be aware that this list still contains User objects
(not strings!), but the Python shell shows you their string
representations when printing.
endorse(other <User object, skill <string)
● Endorse other for skill
● If other doesn’t already have that skill, add it to their skill
dictionary first and then add the user
connect(other <User object)
● Connect with other (add User object to your network and add
yourself to their network)
● If you're already connected, nothing should happen
add_skill(skill <string)
● Add skill to dictionary of user’s skills (skills should begin
with no endorsements)
● If the user already has skill, nothing should happen
connect_with_coworkers(network<LinkedIn object)
● Connect with all other Users in network who work for the same
company as User (if not already connected)
● If User is unemployed, nothing should happen
Company
The Company class is used to represent a Company that a User works for. It has the
following attributes: a name, employees who work at this company, and preferred skills
for this company. Once a User object has been created, they can be hired at a specific
company using the Company class’ hire method.
Attributes
● Name: Name of the company
● preferred_skills: List of skills that the company prefers its
employees to have
● employees: List of users who work at this company
Methods
__init__()
● Name: <string
● preferred_skills: <list of skills (strings) to look for in
Users when recruiting
● employees: <list of User objects employed @ Company. Should be
empty when Company object is first instantiated.
__repr__()
● Return representation of Company in the following format:
● “A Company called [company name] with [# of employees]
employee(s)”
recruit(network<LinkedIn object)
● Return a list of all the User objects in network that have at
least one of the Company’s preferred skills
hire(employee <User object)
● Add employee to list of employees; change employee’s employer
attribute to Company
● If employee is already employed at Company, nothing should
happen
fire(employee <User object)
● Remove employee from Company’s list of users; change employee’s
employer attribute back to None
● If employee is NOT currently employed at this company, nothing
should happen
downsize(target_num<int)
● Find the employees with the fewest total endorsements for their
skills (if there are ties, get the ones with names earliest in
the alphabet) and fire them until Company is down to target_num
employees
● If the target_num is greater than the current number of
employees, nothing should happen
LinkedIn
The LinkedIn class is used to represent an entire LinkedIn network. It only has one
attribute: a simple list of all the User objects that belong to the LinkedIn instance. The
LinkedIn class is able to perform searches for Users in the network with a certain skill,
find all unemployed Users in the network, and add Users to the network, among other
methods.
Attributes
● users : List of all the users that belong to this network
Methods
__init__
● users : <list of User objects The list begins as an empty list
when the LinkedIn object is instantiated. Users are added to
the network through the add_to_network function (see below)
__repr__
● Return representation of LinkedIn in the following format:
● “A LinkedIn network with [# of Users] users.”
search(skill<str, num<int)
● Return list of User objects with specified skill endorsed more
than num times
find_unemployed()
● Return list of all the User objects that are unemployed
strengthen_network()
● Return the number of User objects that have less than 3
connections
add_to_network(users <List of Users)
● Add all User objects in users to LinkedIn network if they aren’t
already in it
● DO NOT add duplicates
get_employees(company <Company object)
● Return list of all the User objects that work for company
Grading Rubric
User
- __init__ 5
- __repr__ 5
- endorse 5
- connect 5
- add_skill 5
- connect_with_coworkers 10
Company
- __init__ 5
- __repr__ 5
- recruit 5
- hire 5
- fire 5
- downsize 10
LinkedIn
- __init__ 5
- __repr__ 5
- find_unemployed 5
- strengthen_network 5
- add_to_network 5
- get_employees 5
Provided
The following file(s) have been provided to you. There are several, but you will only edit one of them:
1.HW10.py
This is the file you will edit and implement. All instructions for what the methods should do are in the
docstrings.
2. hw_10_test.py
In this file we have created a series of tests for your usage. Feel free to add your own tests to the file
to cover any additional cases you would like to test. To test your code, all you have to do is have the
linked_in.py and the hw_10_test.py files in the same directory. Open and run hw_10_test.py. After
running the test, you should see the results. Check the results and start debugging if needed. Read
more about unittest here: [ https://docs.python.org/3/library/unittest.html ]
Disclaimer: The tests found in hw_10_test.py are not intended to be an exhaustive list of all
test cases and does not guarantee any type of grade. Write your own tests if you wish to
ensure you cover all edge cases.
Deliverables
You must submit all of the following file(s). Please make sure the filename matches the filename(s)
below. Be sure you receive the confirmation email from T-Square, and then download your uploaded
files to a new folder and run them.
1. HW10.py
If your file is named something else, you will get a 0%. If this file does not run (if it encounters an
error while trying to run), you will get no credit on the assignment.