In Python:

Goals

At the completion of this assignment, you should:

• have gained additional experience working with and manipulating data read from a file
• have gained additional experience using input using while and conditional statements
• have gained experience closing a file
• have gained experience creating and using a Python module
• have gained additional experience creating a generic function and creating more specific functions that use the generic function
• have gained additional experience formatting output without using tabs
• have gained additional experience working with logical operators
• have gained additional experience working with conditions
• have gained additional experience working with loops and in operators
• have gained experience using an online website to generate random integers and creating a text file containing those integers, as well as a "comment" line
• have gained additional experience with guardian, traversal, search and counter patterns
• have practiced outlining the steps and including those steps as comments in your code
• have gained experience interpreting requirements and implementing those requirements in code

Getting Started

For this assignment you will be working with files, as well as learning to create a shared code file.

You should take the time to consider the steps involved in solving this assignment, and include those steps as single-line comments in your code to help guide you through implementing the coded solution.

You should not attempt to write an entire coded solution; instead, practice incremental development, adding small amounts of code that you can test and validate.

We will be using a URL to generate random data utilizing the free services of RANDOM.ORG (Links to an external site.).

Assignment

Part I: Random Number File

You will need to create a file containing a list of random integers.

• Create random_numbers.txt file using IDLE Editor
• Use your browser to go to the following URL

URL: https://www.random.org/integers/?num=100&min=1&max=100&col=1&base=10&format=plain&rnd=new (Links to an external site.)

• Copy the integers listed on the web page, and paste those numbers into random_numbers.txt.
• Above the numbers at the top of random_numbers.txt add the URL, but insert a # before the URL to indicate this line is a comment and not a number.

# https://www.random.org/integers/?num=100&min=1&max=100&col=1&base=10&format=plain&rnd=new

Part II: Read and Process File Contents

You will need to read each line of the file, skipping any "comment" lines, counting the number of integers, the number of comment lines, and the total of all of the integers. You will then output the number of integers and comments, the total, and the average of all of the integers rounded to two decimal places.

• Create cis122-assign06-random.py file using IDLE Editor
• Open the file and read each line (recommend using the in operator)
• Count the number of lines that start with a # (comment lines)
• Count the number of lines that are not comments
• Sum the values of all non-comment lines

Part III: Print Results

You will need to print the results. The printed results will need to be formatted, but initially simply print the results.

Below is an example of the required output. Note that the average calculation must be rounded to two decimal places.

Part IV: Python Shared Code Module

Before formatting the output, you will create a Python module file containing functions to assist with producing formatted output. You will use the import statement to include code from your Python module.

• Create cis122_assign06_shared.py file using IDLE Editor
  • Note: An underscore is required rather than a dash in a module filename.
• Create the following three functions:
  • pad_string(): Parameters include data to be formatted, the size of the format space, a direction (e.g. left padded or right padded), and the padding character; direction must default to left padded, and the padding character must default to a single space; if the the length of the data to be formatted is greater than the size of the format space, simply return the original data to be formatted
  • pad_left(): Parameters include data to be formatted, the size of the format space, and the padding character; call pad_string(), passing the data, size and formatting character, and explicitly set the padding direction to left padded
  • pad_right(): Parameters include data to be formatted, the size of the format space, and the padding character; call pad_string(), passing the data, size and formatting character, and explicitly set the padding direction to right padded

You should first create and test pad_string(), then add and test pad_left() and pad_right().

To test your code module, you could add test code to your Python code, but you can also simply run the module. No output will appear in the IDLE Shell as the file only contains function definitions; however, once executed, you can use the functions directly in the IDLE Shell.

Part V: Format Printed Output

Revisit your code that prints the results and apply both pad_left() and pad_right() functions to format your output to match the output below (your total and average values will be different).

• Use the import function to include the module. Only import the pad_left() and pad_right() functions.

from cis122_assign06_shared import pad_left, pad_right

• Use the functions as expressions to format the printed output
• Use 10 as the padding space for both pad_left() and pad_right(), but rather than code 10 directly into each function call, create two variables, label_spacing and num_spacing,that may be easily changed to adjust the formatting.

Part VI: Input Filename

Add a while loop to prompt for the integers filename. You will use guardian code to test if no filename was entered and exit the program. You will also add code to close the file.

• Add a while loop that prompts for the integers filename using the prompt below:

• Use the strip() method to remove leading and trailing white space
• Use break to exit the program if no filename is entered
• Use the close() method to close the file object once you've completed reading the file
• Once the file has been read, closed, and results printed, re-prompt for the filename.

Part VII: Test File Existence

Even though you will only read a single file, you should check to see if the file exists before attempting to open the file. We will use the os Python library to test if the file exists, specifically using os.path.exists() method. Note that the path object is an object found in the os library.

• Add an import statement for the os library to your Python file

import os

• Add a conditional statement that tests for the existence of the entered file. You may want to consider an elif and the not operator. Use the following expression to test for existence of a file where the name of the file is stored in a variable filename.

os.path.exists(filename)

• Output the following error message with the name of the invalid file if the file does not exist, and re-prompt for the input file.