IS 210 Assignment #03

Warm-Up Tasks

College:	CUNY School of Professional Studies
Course-Name:	Software Application Programming II
Course-Code:	IS 210
Lesson:	03
Points:	15
Due-Date:	2015-02-17T09:00:00

Overview

The warm-up tasks this week will focus on general git repository tasks. You'll be tasked to manipulate files with git's tools prior to submitting the work through the git pull request workflow.

Instructions

The following tasks will either have you interacting with existing files in the assignment repository or creating new ones on the fly. Don't forget to add your interpreter directive, utf-8 encoding, and a short docstring with any new files that you create!

Important

In these exercises, you may, on occasion, come across a task that requres you to research or use a function or method not directly covered by the course text. Since Python is such a large language it would be impossible for the author to have included descriptions of each and every available function which would largely duplicate the offical Python documentation.

A vital skill to successful programming is being comfortable searching for and using official language documentation sources like the Python String Documentation page. Throughout our coursework we will be practicing both the use of the language in practice and the search skills necessary to become functional programmers.

Warm-Up Tasks

Task 01

In the reading, we learned that python strings are immutable, meaning they cannot be changed. Here we'll test for the same property to see if it holds true for the variables that hold strings.

Specifications

1. Open task_01.py

2. After line 9, add a new line and assign a new value of Nevermore! to the RAVEN variable.

   Note

   Do not change the existing variable declaration. Add a new line instead.

Examples

>>> print RAVEN
Nevermore!

Task 02

Python's order of operations respects parentheses. Create a mathematical statement in a single-line.

Specifications

1. Create a new file task_02.py
2. Create a variable named WEEKS and, in a single statement:
   1. Calculate the remainder of 19 divided by 10
   2. Add the result to 100
   3. Add that result to 2^8 (do exponentiation in Python!)
   4. Divide all of the above by 7

Examples

>>> print WEEKS
52

Task 03

In this task, we'll perform a basic slice operation with a string.

Specifications

1. Open task_03.py
2. Use the slice syntax to slice the first 7 characters from the WILL_ROBINSON variable and assign the result into a new variable named KLAXON

Examples

>>> print WILL_ROBINSON
Danger Will Robinson!
>>> print KLAXON
Danger

Task 04

Next, we'll try repeating a string. This particular file uses an import to take the KLAXON variable you created in Task 03.

Specifications

1. Open task_04.py
2. On a new line, use the string repetition operator to repeat KLAXON five times and save the result back into KLAXON

Hint

While not required to achieve this objective, you could use an arithmetic assignment operator to achieve this objective.

Examples

>>> print KLAXON
Danger Danger Danger Danger Danger

Task 05

The split() string function allows us to split a string according to a specified delimiter and returns a list of the split statements.

Specifications

1. Open task_05.py
2. Use the string .split() program to split up the TEENAGE_MUTANT_NINJAS variable using a period + space '. ' as the delimiter.
3. Save the result into a new variable named TURTLE_POWER

Examples

>>> print TURTLE_POWER
['Michaelangelo', 'Leonardo', 'Rafael', 'Donatello',
 'Heroes in a half shell.']

Task 06

In this task we're going to use the len() function to tell us how many words are found in our copy of Tolstoy's War and Peace.

Specifications

1. Open task_06.py
2. Add a new line and, in a single line, split the text with split() and use len() to count the number of words.
3. Save the resulting number in a new variable named WORDCT

Hint

Python allows you to have multiple functions in the same line

Note

While we won't get to this much later, as you can see, opening files and reading their contents in Python can be very easy to accomplish!

Examples

>>> print WORDCT
566316

Task 07

In this task, we'll use the in operator to test whether or not a particular string is found within another string.

Specifications

1. Open task_07.py
2. Use the in operator to test whether or not the word granaries exists within the WORDS variable
3. Save the result into a variable named GRANARIES_EXIST

Examples

>>> print GRANARIES_EXIST

Task 08

The strip() commands are of great help when dealing with poorly formatted data.

Specifications

1. Open task_08.py
2. Use the strip() function to remove whitespace from NERVOUS_AS and save the result back into the NERVOUS_AS variable
3. In a single-line statement, use rstrip() and lstrip() to remove the commas (,), and forward slashes (/) from NERVOUS_AS storing the result back into the NERVOUS_AS variable.

Note

Depending upon what a function returns, it is possible to chain together multiple function calls as a form of shorthand. This is possible because these functions either return the original object or an object of the exact same time (eg, a string) so subsequenct .function() calls may be strung together one after another.

Examples

>>> print NERVOUS_AS
A long-tailed cat in a room full of rockin' chairs.

Task 09

One way to achieve a multi-line string is to use triple double or single quotes. This is most commonly docstrings which are a required part of every module.

Specifications

1. Open task_09.py
2. Add a multi-line docstring to task_09.py. The docstring should break across two paragraphs.
3. If you want to test your docstring, try the following commands from the Python interactive command line by using help().

Examples

>>> import task_09
>>> help(task_09)

Press q to exit the help page for this module.

Task 10

One of the simple, though useful, string functions available in Python are the casing functions such as .lower() and .upper().

Specifications

1. Open task_10.py
2. Use a string function that will change MOVIE to titlecase and save its result into a new variable named ENTITLED

Examples

>>> print ENTITLED
Dr. Strangelove Or: How I Learned To Stop Worrying And Love The Bomb

Task 11

Learning how to escape special characters and strings is an absolute necessity for any beginning programmer.

Specifications

1. Create a new file called task_11.py
2. Create a new variable called ESCAPE_STRING with the value \n'"

Note

In this case, we want the real characters backslash + n, not the escape sequence of a newline.

Examples

>>> print ESCAPE_STRING
\n'"

Task 12

In this task, we'll assign some simple numeric types. You'll need to use the import statement as shown in your course text or video to get access to the decimal and fraction types.

Specifications

1. Create a new file called task_12.py
2. Create a new variable named INTVAL and assign it a value of 1
3. Create a new variable named FLOATVAL and assign it a value of 0.1
4. Create a new variable named DECVAL and assign it a value of one-tenth
5. Create a new variable named FRACVAL and assign it a value of one-tenth

Hint

You must import both the decimal and fractions modules to get access to the Decimal and Fraction data types.

Examples

>>> print INTVAL
1
>>> print FLOATVAL
0.1
>>> print DECVAL
0.1
>>> print FRACVAL
1/10

Task 13

Testing equality can be tricky with the various mathematical types as they all store data in slightly different ways. Here's we'll take a look at a few cases from what you did in a prior step.

Specifications

1. Open task_13.py, this file imports all of the variables you set in task_12.py
2. Use the equality comparison operator (==) to test if DECVAL and FRACVAL are equal.
3. Save the result into a new variable named, FRAC_DEC_EQUAL
4. Similarly, use the inequality comparison operator (!=) to test if DECVAL and FLOATVAL are inequal
5. Save the result into a new variable named, DEC_FLOAT_INEQUAL

Hint

You can access task_12 data through its namespace so, for example, to access the FLOATVAL variable from task_12, you'd do so through something like task_12.FLOATVAL. Use this way of addressing the variables directly; don't reassign them to new variable names.

Examples

>>> FRAC_DEC_EQUAL
False
>>> DEC_FLOAT_INEQUAL
True

Task 14

There are just a few more basic types with which we ought to familiarize ourselves at this point.

Specifications

1. Create a new file named task_14.py
2. Create a new variable named IS_TRUE and assign it a value of True
3. Create a new variable named IS_FALSE and assign it a value of False
4. Create a new variabled named IS_NONE and assign it a value of None
5. In a single, one-line statement, use the logical AND operator and the equality operator to test if IS_TRUE is equal to 1 and IS_FALSE is equal to 0
6. Store the result into a new variable named INTEGER_EQUIV

Examples

>>> print IS_TRUE
True
>>> print IS_FALSE
False
>>> print IS_NONE
None
>>> INTEGER_EQUIV
True

Task 15

The course text mentions that some types of operations are illegal between objects of different types. For example, a string cannot be concatenated with an integer using the concatenation operator (+) without first converting the integer to a string.

Specifications

1. Open task_15.py
2. Concatenate the variables NOT_THE_QUESTION and ANSWER by using the concatenation operator and the str() function.
3. Store the result into a new variable named THANKS_FOR_THE_FISH

Examples

>>> print THANKS_FOR_THE_FISH
The answer to life, the universe, and everything? It's 42

Executing Tests

Code must be functional and pass tests before it will be eligible for credit.

Linting

Lint tests check your code for syntactic or stylistic errors To execute lint tests against a specific file, simply open a terminal in the same directory as your code repository and type:

$ pylint filename.py

Where filename.py is the name of the file you wish to lint test.

Unit Tests

Unit tests check that your code performs the tested objectives. Unit tests may be executed individually by opening a terminal in the same directory as your code repository and typing:

$ nosetests tests/name_of_test.py

Where name_of_test.py is the name of the testfile found in the tests directory of your source code.

Running All Tests

All tests may be run simultaneously by executing the runtests.sh script from the root of your assignment repository. To execute all tests, open a terminal in the same directory as your code repository and type:

$ sh runtests.sh

Submission

Code should be submitted to GitHub by means of opening a pull request.

As-of Lesson 02, each student will have a branch named after his or her GitHub username. Pull requests should be made against the branch that matches your GitHub username. Pull requests made against other branches will be closed. This work flow mimics the steps you took to open a pull request against the pull branch in Week Two.

For a refresher on how to open a pull request, please see homework instructions in Lesson 01. It is recommended that you run PyLint locally after each file is edited in order to reduce the number of errors found in testing.

In order to receive full credit you must complete the assignment as-instructed and without any violations (reported in the build status). There will be automated tests for this assignment to provide early feedback on program code.

When you have completed this assignment, please post the link to your pull request in the body of the assignment on Blackboard in order to receive credit.