! CSC148H1 S Pages Assignment 0
Assignment 0
Assignment 0: The Gym
Due date: Tuesday, January 28, 2020 before noon sharp (not 12:10)
You must complete this assignment individually. Partners will be permitted only on Assignments 1 and 2.
Learning goals
This assignment is called “Assignment 0” because it is considerably smaller than Assignments 1 and 2. Its purpose
is to make sure that you have understood the basics of object-oriented programming in Python and are ready to
move on with the more advanced topics in the course. By the end of this assignment you should be able to:
Implement a class in Python from a provided interface, including:
Using instance attributes that enable the class methods to provide their services to client code,
Enforcing representation invariants that record important facts about implementation decisions, and
Implementing initializers and other methods
Choose unit tests that can convincingly demonstrate that a method works according to its docstring for all
possible inputs
Implement those test cases in pytest
Interpret the results of doctests and unit tests to assess the correctness of methods
You should also have developed these habits:
Implementing tests for a method before implementing the method
Running your test suite throughout the development of your code
The domain
In this assignment, you will work with three Python classes that manage the schedule of a gym. A Gym consists of
many rooms and each room has a maximum capacity. The gym follows a Schedule where, at different times in the
day, a room may have a Workout Class scheduled in it. A workout class is taught by an Instructor provided they
have the proper qualifications (in the form of certificates) to teach it. A gym offering is a workout class taking
place in a specific room, at a specific time, and taught by a specific instructor. Clients can register for these
offerings provided there is enough space in the room.
We will assume that all offerings begin on the hour and last for 1 hour. We will also assume that all rooms have a fixed
capacity (i.e., the room capacity does not change for different workout classes).
The program
The code consists of three Python classes:
An instance of WorkoutClass represents a type of workout class that can be offered at a gym, such as
advanced pilates . It is worthy of being a Python class rather than just a string because it stores information
about the qualifications required for teaching that type of workout class.
An instance of Instructor represents an instructor who may teach classes at a gym.
An instance of Gym represents a gym, with all of its instructors and its schedule of workout classes. It contains
instances of the other classes.
The code for WorkoutClass has been completed for you. But many methods for the Instructor and Gym classes
are missing their implementation.
Representing the data
We have already decided how data will be represented for you in this assignment. For example, clients are
represented as strings and instructors are represented as a custom Python class. You should read the provided
starter code carefully to see how all the data is stored.
The most complex data structure is referred to by the _schedule attribute in the Gym class. The diagram below
should help you visualize the data structure:
Input to the program
Input to the program comes from a file. We have provided a function called load_data that reads and parses an
input file, and returns a Gym object that represents all the information in that file. The load_data function calls a
number of helper functions, and uses the three Python classes to build up the instance of Gym to be returned.
The starter code contains an example input file. It contains multi-line chunks of data separated by an extra
newline character (which give the appearance of a blank line). Each chunk begins with one of five strings
( Instructor , Class , Room , Offerings , or Registrations ) and is followed by information defining the described
thing. Each chunk is parsed differently depending on how it begins. The code handles any input file that follows
this format.
Although we have provided all the code for reading a gym data file, we recommend that you review this code
(especially if you are not confident about reading from files in Python).
Note that some sections of the input file include date and time values, such as ‘2020-01-14 09:00’ . The code we
have provided sends both a specific date and time string (such as ‘2020-01-14 09:00’ ) and a string specifying its
format (our code expects the input file to follow the format ‘%Y-%m-%d %H:%M’ ) to the function
datetime.strptime . The function returns an instance of class datetime that represents the given date and time.
See the Python documentation for more details.
This format is case-sensitive (e.g., the datetime library represents a month with %m and a minute with %M ).
Your task
Save a0.zip to your computer and extract its contents. Copy all the extracted files and folders into your
csc148/assignments/a0 folder. Specifically, a0.zip includes:
gym.py : Starter code that you will complete and submit.
a0_sample_test.py : Some basic tests cases that you will add to.
athletic-centre.txt : An example data file that you can use to run your program.
For reference: A document describing the class design recipe that we use in this course, and the code example
that it uses.
Your tasks are to:
1. Implement the methods defined in class Instructor . There are many ways we could have chosen to
represent the data, and you may find it interesting to consider alternatives. But you must use the attributes
that we defined in the class docstring, and must ensure that the representation invariants hold at all times in
between method calls. Do not add any new attributes to this class.
2. Implement the methods defined in class Gym . Again, you must use the attributes that we defined in the class
docstring, and must ensure that the representation invariants hold at all times in between method calls. Do
not add any new attributes to this class. Class Gym will use class Instructor and WorkoutClass heavily, but it
must not use any of their private attributes.
If a docstring does not specify what to do in a particular scenario, you may decide what the method will do (we
won’t test that scenario). You are welcome, and encouraged, to add private helper methods as you see fit.
However, you must not add any public methods.
Helpful hints
The trickiest part of this assignment is the nested structures in class Gym . It will help immensely if you can keep
straight which data (and type) you are referring to at each moment in the code. A local variable inside your
methods doesn’t have a type contract to help, so use a carefully chosen name to remind you what kind of object it
is.
You may find the following useful. When you are iterating over a compound object (e.g., a list of tuples, a
dictionary), you can extract its pieces in the for statement. Here are some examples:
# Example 1 – List of Tuples
world = [(‘AFG’, ‘Afghanistan’, 22720000),
(‘CAN’, ‘Canada’, 31147000),
(‘ARG’, ‘Argentina’, 37032000),
(‘GHA’, ‘Ghana’, 20212000)]
for code, countryName, population in world:
# Loop body omitted.
# Example 2 – Dictionary
code_to_continent = {‘AFG’: ‘Asia’,
‘CAN’: ‘North America’,
‘ARG’: ‘South America’,
‘GHA’: ‘Africa’
}
for code, continent in code_to_continent.items():
# Loop body omitted.
A list of tuples can be sorted. If you call the sort method on a list of tuples it will, by default, sort based on the
first element of the tuple. For example,
>>> world = [(‘AFG’, ‘Afghanistan’, 22720000),
(‘CAN’, ‘Canada’, 31147000),
(‘ARG’, ‘Argentina’, 37032000),
(‘GHA’, ‘Ghana’, 20212000)]
>>> world.sort()
>>> print(world)
[(‘AFG’, ‘Afghanistan’, 22720000), (‘ARG’, ‘Argentina’, 37032000),
(‘CAN’, ‘Canada’, 31147000), (‘GHA’, ‘Ghana’, 20212000)]
About testing
Be sure to test your code thoroughly. For methods that we outline in the starter code, you may use our doctests
and our tests in a0_sample_test.py as a starting point, but you should augment these with much more thorough
testing of your own. For any helper methods that you define, you will be starting from scratch with the testing.
Your assignment grade will be based on the autotesting that we do, and you can be sure we’ll try to break your code
as hard as we can, so you should also!
The most efficient way to produce code that works is to create and run your test cases as early as possible, and to
re-run them after every change to your code.
Polish!
Take some time to polish up. This step will improve your mark, but it also feels so good. Here are some things you
can do:
Pay attention to any violations of the Python style guidelines that PyCharm points out. Fix them!
In each module, run the provided python_ta.check_all() code to check for errors. Fix them!
Check your docstrings for any helper methods you wrote to make sure they are precise and complete, and
that they follow the conventions of the Function Design Recipe and the Class Design Recipe.
Read through and polish your internal comments.
Remove any code you added just for debugging, such as calls to the print function.
Remove any pass statement where you have added the necessary code.
Remove the word “TODO” wherever/whenever you have completed the task.
Take pride in your gorgeous code!
Submission instructions
1. Login to MarkUs.
2. DOES YOUR CODE RUN PROPERLY on the Teaching Lab machines?! Your code will be tested on the Teaching
Lab machines, so it must run in that environment. Check again before submitting.
3. Submit the file gym.py .
4. On a Teaching Lab machine, download the file you submitted into a brand-new folder, and test your code
thoroughly again to be sure that you submitted the correct version of the correct file. If you accidentally
submit the starter code, for example, you will get 0 for the assignment. 🙁
5. Congratulations, you are finished with your first assignment in CSC148! Go have some chocolate or do a
cartwheel. 🙂
For course-related questions, please contact csc148-2020-01 at cs.toronto.edu.
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