IS 210 Assignment #03

Synthesizing Tasks

College:	CUNY School of Professional Studies
Course-Name:	Software Application Programming I
Course-Code:	IS 210
Lesson:	03

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.

Synthesizing Tasks

Task 01

Python's .replace() string function is a helpful, albeit simple, function for replacing parts of a string. Complex string replacement is best accomplished with the re module, but .replace() certainly has its place in the toolbelt as it noticeably outperforms many other string replacement functions in terms of speed.

Specifications

1. Open task_01.py

2. This file imports another module whcih makes the attributes of the imported module available to the current module. The inquisition module imported in task_01.py provides a constant named SPANISH that may be accessed as:

   inquisition.SPANISH

3. Use .replace() to replace all instances of the word surprise with haddock and assign the result into a new variable named FISHY

Examples

>>> print FISHY
Nobody expects the Spanish Inquisition!
Our chief weapon is haddock...
....

Task 02

Using .replace() and re() aren't the only ways to replace values in a string. This task will challenge you to use a combination of .index(), slicing, len(), and concatenation, you can achieve the same effect.

Specifications

1. Open task_02.py
2. Use a combination of .index(), slicing, len(), simple addition, and string concatenation to programmatically replace the first instance of the word Spanish with Flemish in inquisition.SPANISH
3. Save the result to a new variable named FLEMISH

Hint

Start by creating a variable for the string you want to replace ('Spanish') and then calculating its length

Hint

You can use variables containing integers as positions in a slice operation.

Note

While this method may, at first, seem very convoluted, there are some common use-cases for it in functions and loops.

Examples

>>> print FLEMISH
Nobody expects the Flemish Inquisition!
Our chief weapon is surprise...
....

Task 03

The slice operation's step or stride parameter may be used to reverse a string.

Specifications

1. Open task_03.py
2. Use the third parameter of the slice syntax to reverse the order of the characters in the NAPOLEON variable and save the result into a new variable named REVERSED
3. Use the .lower() method to set REVERSED to lowercase and save the result back onto itself.

Examples

>>> print REVERSED
.able was i ere ,i saw elba

Task 04

While concatenation and slicing are certainly acceptable ways to manipulate strings, the preferred means of injecting data into strings is via the .format() method.

Specifications

1. Open task_04.py

2. Modify the NEWS variable so that the last formatting string ({1}) will display its value as a 6-digit number padded with zeros.

3. Use the .format() method to format the NEWS string variable and assign the following values:

   • {friend} => FNAME
   • {0} => NTYPE
   • {1} => RNUM

   Save the result into a new variable named EMAIL

Examples

>>> print EMAIL
Hi Pat! I have *amazing* news! I won the raffle with number 000042!

Task 05

Object identity using is is another form of comparison operation. Unlike its cousin the equality operator (==), is tests if the two things being compared are the exact same object. In many languages this can be thought of as the strict comparison operator (===). This operator can also be modified by the not logical operator to invert the response (eg, is not). This is sometimes a very important distinction as you'll see below.

Specifications

1. Open task_05.py
2. Currently, this code is broken. when is_empty() is passed an empty string it throws an error. Because an empty string still has a length (0), it should instead report True
3. fix the is_empty() function by changing one operator on one line of code so that it only raises an exception when it's passed a non-sequence data type, like an integer. Otherwise, it should correctly report whether or not the passed argument has no length.

Hint

Review the alternative values of booleans.

Hint

If you use python -i to run this code you can use the interactive command line to call is_empty() and pass it any type of data you want including empty string (is_empty('')), non-empty strings (is_empty('apple')), and integers (is_empty(2)).

Hint

Read the docstrings for both functions to get a sense of what they do.

Important

Much of what you see in this file may be new and that's intended. A critical skill for programmers of all aptitudes is the ability to investigate complex codebases and identify a particular feature or fix that is already within the scope of your current skillset. Many codebases are so large it is literally impossible for any one person to have a complete understanding of the system and in such situations, it is important to have the confidence and experience necessary to successfully skim through the unnecessary components.

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:

$ ./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.