Chapter 11 Applied Python Exercise Outline

11.1 Goal

Outline recreating and extending the bash tool head in Python

11.2 Learning Objectives

After going through this chapter, students should be able to:

  • Explain what the tool head does
  • List the different tasks that make up head’s main function
  • State what the assignment is following these chapters

11.3 Intro

One of the strengths of Python that was previously mentioned is its versatility and how it can be used to extend and visualize the results of analyses performed with the command line. Therefore, the overarching goal of these prepwork chapters is to recreate and extend the functionality of a common bash tool using Python. These chapters will guide you through recreating head, adding some functionality outside of the tool’s basic behavior.

As a reminder, head is used to display the first n number of lines in a file. If no number is specified, the tools defaults to displaying 10 lines.

11.4 Coding Blueprint

In these chapters, you will be guided through writing code that does each of the following to recreate head:

  1. displaying every line in an input file
  2. displaying just the first line in an input file
  3. displaying a specified number of lines from the beginning of an input file
  4. displaying a specific number of lines from the beginning of an input file, specifying the number outside of the code itself as an additional input
  5. displaying a default number of lines from the beginning of an input file if another number isn’t specified as an additional input

Then, you will be guided through writing code that extends the recreated head program such that additionally it can

  1. skip a file header before displaying the output

11.5 Final Assignment

Finally, you will be asked to take your recreated head program and edit it such that it would tail an input file instead.

Each of these 7 tasks will focus on using a specific python fundamental or data type like for loops, conditionals, or lists. Each guided chapter will help you to break the task into small manageable pieces, write pseudocode for these smaller tasks, and then build the code. For the final task, you will be asked to both pseudocode and code on your own.

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