Description
Assignment
The purpose of this assignment is to review the Python language features we have studied so far
this semester. Note that it is due two weeks from the day it was assigned. The extended deadline
is for two reasons:
‚ There is a lot of work to be done to complete this assignment.
‚ The last question asks you to apply topics we will cover next week.
Therefore, I strongly suggest that you do not wait a week before getting started. At the same time,
please recognize that I don’t expect you to complete it within a single week.
Many of the activities in this assignment are modified from challenge activities in previous assignments. You should complete each activity as it appears in this document, and not as it appeared
in any previous documents.
This assignment should be completed as a collection of several Python source (.py) files, one of
which should be named main.py and should contain a variety of test cases for the code in your
other files, and another of which should be named tests.py and should contain test cases written
with either the unittest or pytest framework.
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(1) Complete the “Challenge Activities” numbers 2, 3, and 5 from Homework 2 in a file named
triangles.py. They are reproduced here, modified slightly.
‚ Write a function called triangles(n) that, given a positive integer n, produces a
list of the first n triangle numbers. You may assume that n is a positive integer.
‚ Write a function called ctriangles(n) that produces a list identical to
triangles(n), but does so using a single-line list comprehension. Hint: the built-in
function sum(s) is probably useful here.
‚ Write a function called pascal(r) that, given a positive integer r, produces a list
containing the first r rows of Pascal’s Triangle (more precisely, the function should
only generate all non-zero entries in the triangle). You may assume that r is a positive
integer. You should not import any modules to complete this task, including the math
module.
Recall: The kth entry in the nth row of Pascal’s Triangle has the value `
n
k
˘
“
n!
k!pn´kq!
.
It has the nice property that `
n
k
˘
“
`
n´1
k´1
˘
`
`
n´1
k
˘
.
(2) Complete the “Challenge Activities” numbers 18 and 19 from Homework 4. They are reproduced here, modified slightly.
‚ The diceroller function in the Homework 4 template file is fine, but the output
leaves something to be desired. Copy the diceroller function from the Homework
4 template into a file named dice.py. First, replace the mcg pseudorandom number
generator with a better one, such as the random module. Next, add a new function called print_bar_chart(data: dict) that takes, as input, the dictionary
returned by diceroller and prints to the console a horizontal bar chart made of unicode characters. Do not import any charting modules—use only the built-in functions
for dict and str and, if you want, f-strings. A useful character to use as you build
each bar is the Unicode character ‘FULL BLOCK’ (U+2588), which can be included in
Python source as the str literal “\u2588”. Here are the requirements for the printed
chart:
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– There should be one line for each possible roll value, and they should be sorted
in increasing order of roll value.
– Each line should begin with a label (i.e., a roll value) followed by at least one
space, followed by the bar for that value.
– Each bar should be left-aligned in the console.
– Each line should be no more than 80 characters long, including the label.
In listing 1, see an example output based on the dictionary returned by
diceroller(6) (it uses # as the bar character because of limitations in my LATEX
installation, and the line width is only 60 characters because of space limitations on
this page).
Listing 1. Example run of python3 -i dice.py.
>>> for line in diceroller(6, 5000):
… print(line)
…
1 #########################################################
2 ####################################################
3 ######################################################
4 ########################################################
5 #####################################################
6 ######################################################
‚ Copy the generator function words(s) from your solution to Homework 4 into a file
named words.py. If it is not correct, make it correct. Use that generator function
to write a function called firstlines(filename) that builds a dictionary of every
word that appears in a file mapped to the line number on which it first appears. For
example, suppose the contents of the file foo.txt are
this is
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my file
this is not
your file
Then a call to firstlines(“foo.txt”) should produce the dictionary
{’this’: 0, ’is’: 0, ’my’: 1, ’file’: 1, ’not’: 2, ’your’: 3}.
(3) Complete the “Challenge Activities” numbers 11 and 12 from Homework 5 in a file named
fraction.py. They are reproduced here, modified slightly.
‚ Augment the Fraction class with a class method called
from_str(cls, str_rep: str) -> Fraction with the following definition.
@classmethod
def from_str(cls, str_rep: str) -> ’Fraction’:
“””Produces a fraction from string str_rep.
Requires str_rep is in one of two forms.
Either str_rep is the string representation of a fraction
(e.g., ’5/3’ or ’-18/36’),
or str_rep is the string representation of a decimal number
(e.g., ’47.625’ or ’-8.3333’).
The returned fraction should be in reduced form and have the
value one would “expect” from the input string.
“””
‚ Modify the __init__ method of the Fraction class to take either two int arguments or a single str argument, treated as it is in from_str. Hint: use default
parameter values to detect whether the function was called with one or two arguments.
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(4) Modify the from_str method you just wrote to raise a ValueError if the string passed
as an argument is not in one of the acceptable forms.
(5) Starting from your solution to Homework 6, complete the “Challenge Activities” numbers
4 and 5 from Homework 6 in a file named graph.py. They are reproduced here, modified
slightly.
‚ Implement the other two subclasses of Graph.
‚ There are two (non-abstract) functions in the Graph class that are
marked with TODO (challenge) comments: depth_first_search and
breadth_first_search. Implement them as generator functions.
(6) Create a file named main.py that imports the files in which you completed the rest of
the activities, and fill it with test cases for the rest of your code.
(7) Create a file called tests.py that contains test cases for all of your code written in one
of the frameworks we discussed (either unittest or pytest). tests.py should execute
all of the test cases when it is run via python3 test.py.
Challenge Activities
Some homeworks (such as this one) will have additional challenge activities. These activities do
not contribute to your grade, but they are problems that I find interesting or challenging.
(8) Modify your main.py file to execute all of your test cases when it is run via
python3 main.py.
(9) Keeping all of your test cases in a single file is less than ideal, especially when working in
a large project. Reorganize your test cases so that it will remain manageable even when
your project grows. Create a shell script called runtests.sh that, when executed at the
command line, runs all of the test cases in your project. As an added challenge, do it with
a single command (this may involve creating or modifying Python source files).
(10) Complete the rest of the challenge activities from Homeworks 1–6.
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(11) Write a program that takes as input the name of a directory containing a bunch of Python
source files that all expose the same set of functions and classes, and runs a suite of test
cases on each of those files, pausing after each run to allow the user to inspect the result.
Submission
To submit this assignment, upload a .zip file containing all of your Python files to the “Homework 7” assignment on Carmen. As always, be sure to note all group members who contributed to
the assignment and what those contributions were.
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